Summa Th. III EN Qu.35 a.8
Objection: 1. It would seem that Christ was not born at a fitting time. Because Christ came in order to restore liberty to His own. But He was born at a time of subjection---namely, when the whole world, as it were, tributary to Augustus, was being enrolled, at his command as Luke relates (2:1). Therefore it seems that Christ was not born at a fitting time.
2. Further, the promises concerning the coming of Christ were not made to the Gentiles; according to Rm 9,4: "To whom belong . . . the promises." But Christ was born during the reign of a foreigner, as appears from Mt 2,1: "When Jesus was born in the days of King Herod." Therefore it seems that He was not born at a fitting time.
3. Further, the time of Christ's presence on earth is compared to the day, because He is the "Light of the world"; wherefore He says Himself (Jn 9,4): "I must work the works of Him that sent Me, whilst it is day." But in summer the days are longer than in winter. Therefore, since He was born in the depth of winter, eight days before the Kalends of January, it seems that He was not born at a fitting time.
On the contrary It is written (Ga 4,4): "When the fulness of the time was come, God sent His Son, made of a woman, made under the law."
I answer that There is this difference between Christ and other men, that, whereas they are born subject to the restrictions of time, Christ, as Lord and Maker of all time, chose a time in which to be born, just as He chose a mother and a birthplace. And since "what is of God is well ordered" and becomingly arranged, it follows that Christ was born at a most fitting time.
Reply to Objection: 1. Christ came in order to bring us back from a state of bondage to a state of liberty. And therefore, as He took our mortal nature in order to restore us to life, so, as Bede says (Super Luc. ii, 4,5), "He deigned to take flesh at such a time that, shortly after His birth, He would be enrolled in Caesar's census, and thus submit Himself to bondage for the sake of our liberty."Moreover, at that time, when the whole world lived under one ruler, peace abounded on the earth. Therefore it was a fitting time for the birth of Christ, for "He is our peace, who hath made both one," as it is written (Ep 2,14). Wherefore Jerome says on Is 2:4: "Nation shall not lift up sword against nation."Again, it was fitting that Christ should be born while the world was governed by one ruler, because "He came to gather His own [Vulg.: 'the children of God'] together in one" (Jn 11,52), that there might be "one fold and one shepherd" (Jn 10,16).
2. Christ wished to be born during the reign of a foreigner, that the prophecy of Jacob might be fulfilled (Gn 49,10): "The sceptre shall not be taken away from Juda, nor a ruler from his thigh, till He come that is to be sent." Because, as Chrysostom says (Hom. ii in Matth. [*Opus Imperf., falsely ascribed to Chrysostom]), as long as the Jewish "people was governed by Jewish kings, however wicked, prophets were sent for their healing. But now that the Law of God is under the power of a wicked king, Christ is born; because a grave and hopeless disease demanded a more skilful physician."
3. As says the author of the book De Qq. Nov. et Vet. Test., "Christ wished to be born, when the light of day begins to increase in length," so as to show that He came in order that man might come nearer to the Divine Light, according to Lc 1,79: "To enlighten them that sit in darkness and in the shadow of death."In like manner He chose to be born in the rough winter season, that He might begin from then to suffer in body for us.
We must now consider the manifestation of the newly born Christ: concerning which there are eight points of inquiry:
(1) Whether Christ's birth should have been made known to all?
(2) Whether it should have been made known to some?
(3) To whom should it have been made known?
(4) Whether He should have made Himself known, or should He rather have been manifested by others?
(5) By what other means should it have been made known?
(6) Of the order of these manifestations;
(7) Of the star by means of which His birth was made known;
(8) of the adoration of the Magi, who were informed of Christ's nativity by means of the star.
Objection: 1. It would seem that Christ's birth should have been made known to all. Because fulfilment should correspond to promise. Now, the promise of Christ's coming is thus expressed (Ps 49,3): "God shall come manifestly. But He came by His birth in the flesh." Therefore it seems that His birth should have been made known to the whole world.
2. Further, it is written (1Tm 1,15): "Christ came into this world to save sinners." But this is not effected save in as far as the grace of Christ is made known to them; according to Titus 2:11,12: "The grace of God our Saviour hath appeared to all men, instructing us, that denying ungodliness and worldly desires, we should live soberly, and justly, and godly in this world." Therefore it seems that Christ's birth should have been made known to all.
3. Further, God is most especially inclined to mercy; according to Ps 144,9: "His tender mercies are over all His works." But in His second coming, when He will "judge justices" (Ps 70,3), He will come before the eyes of all; according to Mt 24,27: "As lightning cometh out of the east, and appeareth even into the west, so shall also the coming of the Son of Man be." Much more, therefore, should His first coming, when He was born into the world according to the flesh, have been made known to all.
On the contrary It is written (Is 45,15): "Thou art a hidden God, the Holy [Vulg.: 'the God] of Israel, the Saviour." And, again (Is 43,3): "His look was, as it were, hidden and despised."
I answer that It was unfitting that Christ's birth should be made known to all men without distinction. First, because this would have been a hindrance to the redemption of man, which was accomplished by means of the Cross; for, as it is written (1Co 2,8): "If they had known it, they would never have crucified the Lord of glory."Secondly, because this would have lessened the merit of faith, which He came to offer men as the way to righteousness. according to Rm 3,22: "The justice of God by faith of Jesus Christ." For if, when Christ was born, His birth had been made known to all by evident signs, the very nature of faith would have been destroyed, since it is "the evidence of things that appear not," as stated, He 11,1.Thirdly, because thus the reality of His human nature would have come into doubt. Whence Augustine says (Ep ad Volusianum cxxxvii): "If He had not passed through the different stages of age from babyhood to youth, had neither eaten nor slept, would He not have strengthened an erroneous opinion, and made it impossible for us to believe that He had become true man? And while He is doing all things wondrously, would He have taken away that which He accomplished in mercy?"
Reply to Objection: 1. According to the gloss, the words quoted must be understood of Christ's coming as judge.
2. All men were to be instructed unto salvation, concerning the grace of God our Saviour, not at the very time of His birth, but afterwards, in due time, after He had "wrought salvation in the midst of the earth" (Ps 73,12). Wherefore after His Passion and Resurrection, He said to His disciples (Mt 28,19): "Going . . . teach ye all nations."
3. For judgment to be passed, the authority of the judge needs to be known: and for this reason it behooves that the coming of Christ unto judgment should be manifest. But His first coming was unto the salvation of all, which is by faith that is of things not seen. And therefore it was fitting that His first coming should be hidden.
Objection: 1. It would seem that Christ's birth should not have been made known to anyone. For, as stated above (Article , ad 3), it befitted the salvation of mankind that Christ's first coming should be hidden. But Christ came to save all; according to 1Tm 4,10: "Who is the Saviour of all men, especially of the faithful." Therefore Christ's birth should not have been made known to anyone.
2. Further, before Christ was born, His future birth was made known to the Blessed Virgin and Joseph. Therefore it was not necessary that it should be made known to others after His birth.
3. Further, no wise man makes known that from which arise disturbance and harm to others. But, when Christ's birth was made known, disturbance arose: for it is written (Mt 2,3) that "King Herod, hearing" of Christ's birth, "was troubled, and all Jerusalem with him." Moreover, this brought harm to others; because it was the occasion of Herod's killing "all the male children that were in Bethlehem . . . from two years old and under." Therefore it seems unfitting for Christ's birth to have been made known to anyone.
On the contrary Christ's birth would have been profitable to none if it had been hidden from all. But it behooved Christ's birth to be profitable: else He were born in vain. Therefore it seems that Christ's birth should have been made known to some.
I answer that As the Apostle says (Rm 13,1) "what is of God is well ordered." Now it belongs to the order of Divine wisdom that God's gifts and the secrets of His wisdom are not bestowed on all equally, but to some immediately, through whom they are made known to others. Wherefore, with regard to the mystery of the Resurrection it is written (Ac 10,40-41): "God . . . gave" Christ rising again "to be made manifest, not to all the people, but to witnesses pre-ordained by God." Consequently, that His birth might be consistent with this, it should have been made known, not to all, but to some, through whom it could be made known to others.
Reply to Objection: 1. As it would have been prejudicial to the salvation of mankind if God's birth had been made known to all men, so also would it have been if none had been informed of it. Because in either case faith is destroyed, whether a thing be perfectly manifest, or whether it be entirely unknown, so that no one can hear it from another; for "faith cometh by hearing" (Rm 10,17).
2. Mary and Joseph needed to be instructed concerning Christ's birth before He was born, because it devolved on them to show reverence to the child conceived in the womb, and to serve Him even before He was born. But their testimony, being of a domestic character, would have aroused suspicion in regard to Christ's greatness: and so it behooved it to be made known to others, whose testimony could not be suspect.
3. The very disturbance that arose when it was known that Christ was born was becoming to His birth. First, because thus the heavenly dignity of Christ is made manifest. Wherefore Gregory says (Hom. x in Evang.): "After the birth of the King of heaven, the earthly king is troubled: doubtless because earthly grandeur is covered with confusion when the heavenly majesty is revealed."Secondly, thereby the judicial power of Christ was foreshadowed. Thus Augustine says in a sermon (30 de Temp.) on the Epiphany: "What will He be like in the judgment-seat; since from His cradle He struck terror into the heart of a proud king?"Thirdly, because thus the overthrow of the devil's kingdom was foreshadowed. For, as Pope Leo says in a sermon on the Epiphany (Serm. v [*Opus Imperfectum in Matth., Hom. ii, falsely ascribed to St. John Chrysostom]): "Herod was not so much troubled in himself as the devil in Herod. For Herod thought Him to be a man, but the devil thought Him to be God. Each feared a successor to his kingdom: the devil, a heavenly successor; Herod, an earthly successor." But their fear was needless: since Christ had not come to set up an earthly kingdom, as Pope Leo says, addressing himself to Herod: "Thy palace cannot hold Christ: nor is the Lord of the world content with the paltry power of thy scepter." That the Jews were troubled, who, on the contrary, should have rejoiced, was either because, as Chrysostom says, "wicked men could not rejoice at the coming of the Holy one," or because they wished to court favor with Herod, whom they feared; for "the populace is inclined to favor too much those whose cruelty it endures."And that the children were slain by Herod was not harmful to them, but profitable. For Augustine says in a sermon on the Epiphany (66 de Diversis): "It cannot be questioned that Christ, who came to set man free, rewarded those who were slain for Him; since, while hanging on the cross, He prayed for those who were putting Him to death."
Objection: 1. It would seem that those to whom Christ's birth was made known were not suitably chosen. For our Lord (Mt 10,5) commanded His disciples, "Go ye not into the way of the Gentiles," so that He might be made known to the Jews before the Gentiles. Therefore it seems that much less should Christ's birth have been at once revealed to the Gentiles who "came from the east," as stated Mt 2,1.
2. Further, the revelation of Divine truth should be made especially to the friends of God, according to Job 37 [Vulg.: Jb 36,33]: "He sheweth His friend concerning it." But the Magi seem to be God's foes; for it is written (Lv 19,31): "Go not aside after wizards [magi], neither ask anything of soothsayers." Therefore Christ's birth should not have been made known to the Magi.
3. Further, Christ came in order to set free the whole world from the power of the devil; whence it is written (Ml 1,11): "From the rising of the sun even to the going down, My name is great among the Gentiles." Therefore He should have been made known, not only to those who dwelt in the east, but also to some from all parts of the world.
4. Further, all the sacraments of the Old Law were figures of Christ. But the sacraments of the Old Law were dispensed through the ministry of the legal priesthood. Therefore it seems that Christ's birth should have been made known rather to the priests in the Temple than to the shepherds in the fields.
5. Further, Christ was born of a Virgin-Mother, and was as yet a little child. It was therefore more suitable that He should be made known to youths and virgins than to old and married people or to widows, such as Simeon and Anna.
On the contrary It is written (Jn 13,18): "I know whom I have chosen." But what is done by God's wisdom is done becomingly. Therefore those to whom Christ's birth was made known were suitably chosen.
I answer that Salvation, which was to be accomplished by Christ, concerns all sorts and conditions of men: because, as it is written (Col 3,11), in Christ "there is neither male nor female, [*These words are in reality from Ga 3,28] neither Gentile nor Jew . . . bond nor free," and so forth. And in order that this might be foreshadowed in Christ's birth, He was made known to men of all conditions. Because, as Augustine says in a sermon on the Epiphany (32 de Temp.), "the shepherds were Israelites, the Magi were Gentiles. The former were nigh to Him, the latter far from Him. Both hastened to Him together as to the cornerstone." There was also another point of contrast: for the Magi were wise and powerful; the shepherds simple and lowly. He was also made known to the righteous as Simeon and Anna; and to sinners, as the Magi. He was made known both to men, and to women---namely, to Anna---so as to show no condition of men to be excluded from Christ's redemption.
Reply to Objection: 1. That manifestation of Christ's birth was a kind of foretaste of the full manifestation which was to come. And as in the later manifestation the first announcement of the grace of Christ was made by Him and His Apostles to the Jews and afterwards to the Gentiles, so the first to come to Christ were the shepherds, who were the first-fruits of the Jews, as being near to Him; and afterwards came the Magi from afar, who were "the first-fruits of the Gentiles," as Augustine says (Serm. 30 de Temp. cc.).
2. As Augustine says in a sermon on the Epiphany (Serm. 30 de Temp.): "As unskilfulness predominates in the rustic manners of the shepherd, so ungodliness abounds in the profane rites of the Magi. Yet did this Corner-Stone draw both to Itself; inasmuch as He came 'to choose the foolish things that He might confound the wise,' and 'not to call the just, but sinners,'" so that "the proud might not boast, nor the weak despair." Nevertheless, there are those who say that these Magi were not wizards, but wise astronomers, who are called Magi among the Persians or Chaldees.
3. As Chrysostom says [*Hom. ii in Matth. in the Opus Imperf., among the supposititious works of Chrysostom]: "The Magi came from the east, because the first beginning of faith came from the land where the day is born; since faith is the light of the soul." Or, "because all who come to Christ come from Him and through Him": whence it is written (Zach. 6:12): "Behold a Man, the Orient is His name." Now, they are said to come from the east literally, either because, as some say, they came from the farthest parts of the east, or because they came from the neighboring parts of Judea that lie to the east of the region inhabited by the Jews. Yet it is to be believed that certain signs of Christ's birth appeared also in other parts of the world: thus, at Rome the river flowed with oil [*Eusebius, Chronic. II, Olymp. 185]; and in Spain three suns were seen, which gradually merged into one [*Cf. Eusebius, Chronic. II, Olymp. 184].
4. As Chrysostom observes (Theophylact., Enarr. in Luc. ii, 8), the angel who announced Christ's birth did not go to Jerusalem, nor did he seek the Scribes and Pharisees, for they were corrupted, and full of ill-will. But the shepherds were single-minded, and were like the patriarchs and Moses in their mode of life.Moreover, these shepherds were types of the Doctors of the Church, to whom are revealed the mysteries of Christ that were hidden from the Jews.
5. As Ambrose says (on Lc 2,25): "It was right that our Lord's birth should be attested not only by the shepherds, but also by people advanced in age and virtue": whose testimony is rendered the more credible by reason of their righteousness.
Objection: 1. It would seem that Christ should have Himself made His birth known. For "a direct cause is always of greater power than an indirect cause," as is stated Phys. viii. But Christ made His birth known through others---for instance, to the shepherds through the angels, and to the Magi through the star. Much more, therefore, should He Himself have made His birth known.
2. Further, it is written (Si 20,32): "Wisdom that is hid and treasure that is not seen; what profit is there in them both?" But Christ had, to perfection, the treasure of wisdom and grace from the beginning of His conception. Therefore, unless He had made the fulness of these gifts known by words and deeds, wisdom and grace would have been given Him to no purpose. But this is unreasonable: because "God and nature do nothing without a purpose" (De Coelo i).
3. Further, we read in the book De Infantia Salvatoris that in His infancy Christ worked many miracles. It seems therefore that He did Himself make His birth known.
On the contrary Pope Leo says (Serm. xxxiv) that the Magi found the "infant Jesus in no way different from the generality of human infants." But other infants do not make themselves known. Therefore it was not fitting that Christ should Himself make His birth known.
I answer that Christ's birth was ordered unto man's salvation, which is by faith. But saving faith confesses Christ's Godhead and humanity. It behooved, therefore, Christ's birth to be made known in such a way that the proof of His Godhead should not be prejudicial to faith in His human nature. But this took place while Christ presented a likeness of human weakness, and yet, by means of God's creatures, He showed the power of the Godhead in Himself. Therefore Christ made His birth known, not by Himself, but by means of certain other creatures.
Reply to Objection: 1. By the way of generation and movement we must of necessity come to the imperfect before the perfect. And therefore Christ was made known first through other creatures, and afterwards He Himself manifested Himself perfectly.
2. Although hidden wisdom is useless, yet there is no need for a wise man to make himself known at all times, but at a suitable time; for it is written (Si 20,6): "There is one that holdeth his peace because he knoweth not what to say: and there is another that holdeth his peace, knowing the proper time." Hence the wisdom given to Christ was not useless, because at a suitable time He manifested Himself. And the very fact that He was hidden at a suitable time is a sign of wisdom.
3. The book De Infantia Salvatoris is apocryphal. Moreover, Chrysostom (Hom. xxi super Joan.) says that Christ worked no miracles before changing the water into wine, according to Jn 2,11: "'This beginning of miracles did Jesus.' For if He had worked miracles at an early age, there would have been no need for anyone else to manifest Him to the Israelites; whereas John the Baptist says (Jn 1,31): 'That He may be made manifest in Israel; therefore am I come baptizing with water.' Moreover, it was fitting that He should not begin to work miracles at an early age. For people would have thought the Incarnation to be unreal, and, out of sheer spite, would have crucified Him before the proper time."
Objection: 1. It would seem that Christ's birth should not have been manifested by means of the angels. For angels are spiritual substances, according to Ps 103,4: "Who maketh His [Vulg.: 'makest Thy'] angels, spirits." But Christ's birth was in the flesh, and not in His spiritual substance. Therefore it should not have been manifested by means of angels.
2. Further, the righteous are more akin to the angels than to any other, according to Ps 33,8: "The angel of the Lord shall encamp round about them that fear Him, and shall deliver them." But Christ's birth was not announced to the righteous, viz. Simeon and Anna, through the angels. Therefore neither should it have been announced to the shepherds by means of the angels.
3. Further, it seems that neither ought it to have been announced to the Magi by means of the star. For this seems to favor the error of those who think that man's birth is influenced by the stars. But occasions of sin should be taken away from man. Therefore it was not fitting that Christ's birth should be announced by a star.
4. Further, a sign should be certain, in order that something be made known thereby. But a star does not seem to be a certain sign of Christ's birth. Therefore Christ's birth was not suitably announced by a star.
On the contrary It is written (Dt 32,4): "The works of God are perfect." But this manifestation is the work of God. Therefore it was accomplished by means of suitable signs.
I answer that As knowledge is imparted through a syllogism from something which we know better, so knowledge given by signs must be conveyed through things which are familiar to those to whom the knowledge is imparted. Now, it is clear that the righteous have, through the spirit of prophecy, a certain familiarity with the interior instinct of the Holy Ghost, and are wont to be taught thereby, without the guidance of sensible signs. Whereas others, occupied with material things, are led through the domain of the senses to that of the intellect. The Jews, however, were accustomed to receive Divine answers through the angels; through whom they also received the Law, according to Ac 7,53: "You [Vulg.: 'who'] . . . have received the Law by the disposition of angels." And the Gentiles, especially astrologers, were wont to observe the course of the stars. And therefore Christ's birth was made known to the righteous, viz. Simeon and Anna, by the interior instinct of the Holy Ghost, according to Lc 2,26: "He had received an answer from the Holy Ghost that he should not see death before he had seen the Christ of the Lord." But to the shepherds and Magi, as being occupied with material things, Christ's birth was made known by means of visible apparitions. And since this birth was not only earthly, but also, in a way, heavenly, to both (shepherds and Magi) it is revealed through heavenly signs: for, as Augustine says in a sermon on the Epiphany (cciv): "The angels inhabit, and the stars adorn, the heavens: by both, therefore, do the 'heavens show forth the glory of God.'" Moreover, it was not without reason that Christ's birth was made known, by means of angels, to the shepherds, who, being Jews, were accustomed to frequent apparitions of the angels: whereas it was revealed by means of a star to the Magi, who were wont to consider the heavenly bodies. Because, as Chrysostom says (Hom. vi in Matth.): "Our Lord deigned to call them through things to which they were accustomed." There is also another reason. For, as Gregory says (Hom. x in Evang.): "To the Jews, as rational beings, it was fitting that a rational animal [*Cf. I 51,1, ad 2]," viz. an angel, "should preach. Whereas the Gentiles, who were unable to come to the knowledge of God through the reason, were led to God, not by words, but by signs. And as our Lord, when He was able to speak, was announced by heralds who spoke, so before He could speak He was manifested by speechless elements." Again, there is yet another reason. For, as Augustine [*Pope Leo] says in a sermon on the Epiphany: "To Abraham was promised an innumerable progeny, begotten, not of carnal propagation, but of the fruitfulness of faith. For this reason it is compared to the multitude of stars; that a heavenly progeny might be hoped for." Wherefore the Gentiles, "who are thus designated by the stars, are by the rising of a new star stimulated" to seek Christ, through whom they are made the seed of Abraham.
Reply to Objection: 1. That which of itself is hidden needs to be manifested, but not that which in itself is manifest. Now, the flesh of Him who was born was manifest, whereas the Godhead was hidden. And therefore it was fitting that this birth should be made known by angels, who are the ministers of God. Wherefore also a certain "brightness" (Lc 2,9) accompanied the angelic apparition, to indicate that He who was just born was the "Brightness of" the Father's "glory."
2. The righteous did not need the visible apparition of the angel; on account of their perfection the interior instinct of the Holy Ghost was enough for them.
3. The star which manifested Christ's birth removed all occasion of error. For, as Augustine says (Contra Faust. ii): "No astrologer has ever so far connected the stars with man's fate at the time of his birth as to assert that one of the stars, at the birth of any man, left its orbit and made its way to him who was just born": as happened in the case of the star which made known the birth of Christ. Consequently this does not corroborate the error of those who "think there is a connection between man's birth and the course of the stars, for they do not hold that the course of the stars can be changed at a man's birth."In the same sense Chrysostom says (Hom. vi in Matth.): "It is not an astronomer's business to know from the stars those who are born, but to tell the future from the hour of a man's birth: whereas the Magi did not know the time of the birth, so as to conclude therefrom some knowledge of the future; rather was it the other way about."
4. Chrysostom relates (Hom. ii in Matth.) that, according to some apocryphal books, a certain tribe in the far east near the ocean was in the possession of a document written by Seth, referring to this star and to the presents to be offered: which tribe watched attentively for the rising of this star, twelve men being appointed to take observations, who at stated times repaired to the summit of a mountain with faithful assiduity: whence they subsequently perceived the star containing the figure of a small child, and above it the form of a cross.Or we may say, as may be read in the book De Qq. Vet. et Nov. Test., qu. lxiii, that "these Magi followed the tradition of Balaam," who said, "'A star shall rise out of Jacob.' Wherefore observing this star to be a stranger to the system of this world, they gathered that it was the one foretold by Balaam to indicate the King of the Jews."Or again, it may be said with Augustine, in a sermon on the Epiphany (ccclxxiv), that "the Magi had received a revelation through the angels" that the star was a sign of the birth of Christ: and he thinks it probable that these were "good angels; since in adoring Christ they were seeking for salvation."Or with Pope Leo, in a sermon on the Epiphany (xxxiv), that "besides the outward form which aroused the attention of their corporeal eyes, a more brilliant ray enlightened their minds with the light of faith."
Objection: 1. It would seem that Christ's birth was made known in an unbecoming order. For Christ's birth should have been made known to them first who were nearest to Christ, and who longed for Him most; according to Sg 6,14: "She preventeth them that covet her, so that she first showeth herself unto them." But the righteous were nearest to Christ by faith, and longed most for His coming; whence it is written (Lc 2,25) of Simeon that "he was just and devout, waiting for the consolation of Israel." Therefore Christ's birth should have been made known to Simeon before the shepherds and Magi.
2. Further, the Magi were the "first-fruits of the Gentiles," who were to believe in Christ. But first the "fulness of the Gentiles . . . come in" unto faith, and afterwards "all Israel" shall "be saved," as is written (Rm 11,25). Therefore Christ's birth should have been made known to the Magi before the shepherds.
3. Further, it is written (Mt 2,16) that "Herod killed all the male children that were in Bethlehem, and in all the borders thereof, from two years old and under, according to the time which he had diligently inquired from the wise men": so that it seems that the Magi were two years in coming to Christ after His birth. It was therefore unbecoming that Christ should be made known to the Gentiles so long after His birth.
On the contrary It is written (Da 2,21): "He changes time and ages." Consequently the time of the manifestation of Christ's birth seems to have been arranged in a suitable order.
I answer that Christ's birth was first made known to the shepherds on the very day that He was born. For, as it is written (Lc 2,8 Lc 2,15-16): "There were in the same country shepherds watching, and keeping the night-watches over their flock . . . And it came to pass, after the angels departed from them into heaven they [Vulg.: 'the shepherds'] said one to another: Let us go over to Bethlehem . . . and they came with haste." Second in order were the Magi, who came to Christ on the thirteenth day after His birth, on which day is kept the feast of the Epiphany. For if they had come after a year, or even two years, they would not have found Him in Bethlehem, since it is written (Lc 2,39) that "after they had performed all things according to the law of the Lord"---that is to say, after they had offered up the Child Jesus in the Temple---"they returned into Galilee, to their city"---namely, "Nazareth." In the third place, it was made known in the Temple to the righteous on the fortieth day after His birth, as related by Luke (2:22).The reason of this order is that the shepherds represent the apostles and other believers of the Jews, to whom the faith of Christ was made known first; among whom there were "not many mighty, not many noble," as we read 1Co 1,26. Secondly, the faith of Christ came to the "fulness of the Gentiles"; and this is foreshadowed in the Magi. Thirdly it came to the fulness of the Jews, which is foreshadowed in the righteous. Wherefore also Christ was manifested to them in the Jewish Temple.
Reply to Objection: 1. As the Apostle says (Rm 9,30-31): "Israel, by following after the law of justice, is not come unto the law of justice": but the Gentiles, "who followed not after justice," forestalled the generality of the Jews in the justice which is of faith. As a figure of this, Simeon, "who was waiting for the consolation of Israel," was the last to know Christ born: and he was preceded by the Magi and the shepherds, who did not await the coming of Christ with such longing.
2. Although the "fulness of the Gentiles came in" unto faith before the fulness of the Jews, yet the first-fruits of the Jews preceded the first-fruits of the Gentiles in faith. For this reason the birth of Christ was made known to the shepherds before the Magi.
3. There are two opinions about the apparition of the star seen by the Magi. For Chrysostom (Hom. ii in Matth. [*Opus Imperf. in Matth., falsely ascribed to Chrysostom]), and Augustine in a sermon on the Epiphany (cxxxi, cxxxii), say that the star was seen by the Magi during the two years that preceded the birth of Christ: and then, having first considered the matter and prepared themselves for the journey, they came from the farthest east to Christ, arriving on the thirteenth day after His birth. Wherefore Herod, immediately after the departure of the Magi, "perceiving that He was deluded by them," commanded the male children to be killed "from two years old and under," being doubtful lest Christ were already born when the star appeared, according as he had heard from the Magi.But others say that the star first appeared when Christ was born, and that the Magi set off as soon as they saw the star, and accomplished a journey of very great length in thirteen days, owing partly to the Divine assistance, and partly to the fleetness of the dromedaries. And I say this on the supposition that they came from the far east. But others, again, say that they came from a neighboring country, whence also was Balaam, to whose teaching they were heirs; and they are said to have come from the east, because their country was to the east of the country of the Jews. In this case Herod killed the babes, not as soon as the Magi departed, but two years after: and that either because he is said to have gone to Rome in the meanwhile on account of an accusation brought against him, or because he was troubled at some imminent peril, and for the time being desisted from his anxiety to slay the child, or because he may have thought that the Magi, "being deceived by the illusory appearance of the star, and not finding the child, as they had expected to, were ashamed to return to him": as Augustine says (De Consensu Evang. ii). And the reason why he killed not only those who were two years old, but also the younger children, would be, as Augustine says in a sermon on the Innocents, because he feared lest a child whom the stars obey, might make himself appear older or younger.
Summa Th. III EN Qu.35 a.8