Summa Th. I-II EN Qu.111 a.3

Whether grace is fittingly divided into prevenient and subsequent grace?


Objection: 1. It would seem that grace is not fittingly divided into prevenient and subsequent. For grace is an effect of the Divine love. But God's love is never subsequent, but always prevenient, according to
1Jn 4,10: "Not as though we had loved God, but because He hath first loved us." Therefore grace ought not to be divided into prevenient and subsequent.
2. Further, there is but one sanctifying grace in man, since it is sufficient, according to 2Co 12,9: "My grace is sufficient for thee." But the same thing cannot be before and after. Therefore grace is not fittingly divided into prevenient and subsequent.
3. Further, grace is known by its effects. Now there are an infinite number of effects---one preceding another. Hence it with regard to these, grace must be divided into prevenient and subsequent, it would seem that there are infinite species of grace. Now no art takes note of the infinite in number. Hence grace is not fittingly divided into prevenient and subsequent.

On the contrary
God's grace is the outcome of His mercy. Now both are said in Ps 58,11: "His mercy shall prevent me," and again, Ps 22,6: "Thy mercy will follow me." Therefore grace is fittingly divided into prevenient and subsequent.
I answer that As grace is divided into operating and cooperating, with regard to its diverse effects, so also is it divided into prevenient and subsequent, howsoever we consider grace. Now there are five effects of grace in us: of these, the first is, to heal the soul; the second, to desire good; the third, to carry into effect the good proposed; the fourth, to persevere in good; the fifth, to reach glory. And hence grace, inasmuch as it causes the first effect in us, is called prevenient with respect to the second, and inasmuch as it causes the second, it is called subsequent with respect to the first effect. And as one effect is posterior to this effect, and prior to that, so may grace be called prevenient and subsequent on account of the same effect viewed relatively to divers others. And this is what Augustine says (De Natura et Gratia xxxi): "It is prevenient, inasmuch as it heals, and subsequent, inasmuch as, being healed, we are strengthened; it is prevenient, inasmuch as we are called, and subsequent, inasmuch as we are glorified."

Reply to Objection: 1.
God's love signifies something eternal; and hence can never be called anything but prevenient. But grace signifies a temporal effect, which can precede and follow another; and thus grace may be both prevenient and subsequent.
The division into prevenient and subsequent grace does not divide grace in its essence, but only in its effects, as was already said of operating and cooperating grace. For subsequent grace, inasmuch as it pertains to glory, is not numerically distinct from prevenient grace whereby we are at present justified. For even as the charity of the earth is not voided in heaven, so must the same be said of the light of grace, since the notion of neither implies imperfection.
Although the effects of grace may be infinite in number, even as human acts are infinite, nevertheless all reduced to some of a determinate species, and moreover all coincide in this---that one precedes another.

Whether gratuitous grace is rightly divided by the Apostle?


Objection: 1. It would seem that gratuitous grace is not rightly divided by the Apostle. For every gift vouchsafed to us by God, may be called a gratuitous grace. Now there are an infinite number of gifts freely bestowed on us by God as regards both the good of the soul and the good of the body---and yet they do not make us pleasing to God. Hence gratuitous graces cannot be contained under any certain division.
Further, gratuitous grace is distinguished from sanctifying grace. But faith pertains to sanctifying grace, since we are justified by it, according to Rm 5,1: "Being justified therefore by faith." Hence it is not right to place faith amongst the gratuitous graces, especially since the other virtues are not so placed, as hope and charity.
3. Further, the operation of healing, and speaking divers tongues are miracles. Again, the interpretation of speeches pertains either to wisdom or to knowledge, according to Da 1,17: "And to these children God gave knowledge and understanding in every book and wisdom." Hence it is not correct to divide the grace of healing and kinds of tongues against the working of miracles; and the interpretation of speeches against the word of wisdom and knowledge.
4. Further, as wisdom and knowledge are gifts of the Holy Ghost, so also are understanding, counsel, piety, fortitude, and fear, as stated above (Question [68], Article [4]). Therefore these also ought to be placed amongst the gratuitous gifts.

On the contrary
The Apostle says (1Co 12,8-10): "To one indeed by the Spirit is given the word of wisdom; and to another the word of knowledge, according to the same Spirit; to another, the working of miracles; to another, prophecy; to another, the discerning of spirits; to another divers kinds of tongues; to another interpretation of speeches."
I answer that As was said above (Article [1]), gratuitous grace is ordained to this, viz. that a man may help another to be led to God. Now no man can help in this by moving interiorly (for this belongs to God alone), but only exteriorly by teaching or persuading. Hence gratuitous grace embraces whatever a man needs in order to instruct another in Divine things which are above reason. Now for this three things are required: first, a man must possess the fullness of knowledge of Divine things, so as to be capable of teaching others. Secondly, he must be able to confirm or prove what he says, otherwise his words would have no weight. Thirdly, he must be capable of fittingly presenting to his hearers what he knows.Now as regards the first, three things are necessary, as may be seen in human teaching. For whoever would teach another in any science must first be certain of the principles of the science, and with regard to this there is "faith," which is certitude of invisible things, the principles of Catholic doctrine. Secondly, it behooves the teacher to know the principal conclusions of the science, and hence we have the word of "wisdom," which is the knowledge of Divine things. Thirdly, he ought to abound with examples and a knowledge of effects, whereby at times he needs to manifest causes; and thus we have the word of "knowledge," which is the knowledge of human things, since "the invisible things of Him . . . are clearly seen, being understood by the things that are made" (Rm 1,20).Now the confirmation of such things as are within reason rests upon arguments; but the confirmation of what is above reason rests on what is proper to the Divine power, and this in two ways: first, when the teacher of sacred doctrine does what God alone can do, in miraculous deeds, whether with respect to bodily health---and thus there is the "grace of healing," or merely for the purpose of manifesting the Divine power; for instance, that the sun should stand still or darken, or that the sea should be divided---and thus there is the "working of miracles." Secondly, when he can manifest what God alone can know, and these are either future contingents---and thus there is "prophecy," or also the secrets of hearts---and thus there is the "discerning of spirits."But the capability of speaking can regard either the idiom in which a person can be understood, and thus there is "kinds of tongues"; or it can regard the sense of what is said, and thus there is the "interpretation of speeches."

Reply to Objection: 1. As stated above (Article [1]), not all the benefits divinely conferred upon us are called gratuitous graces, but only those that surpass the power of nature---e.g. that a fisherman should be replete with the word of wisdom and of knowledge and the like; and such as these are here set down as gratuitous graces.
Faith is enumerated here under the gratuitous graces, not as a virtue justifying man in himself, but as implying a super-eminent certitude of faith, whereby a man is fitted for instructing others concerning such things as belong to the faith. With regard to hope and charity, they belong to the appetitive power, according as man is ordained thereby to God.
The grace of healing is distinguished from the general working of miracles because it has a special reason for inducing one to the faith, since a man is all the more ready to believe when he has received the gift of bodily health through the virtue of faith. So, too, to speak with divers tongues and to interpret speeches have special efficacy in bestowing faith. Hence they are set down as special gratuitous graces.
Wisdom and knowledge are not numbered among the gratuitous graces in the same way as they are reckoned among the gifts of the Holy Ghost, i.e. inasmuch as man's mind is rendered easily movable by the Holy Ghost to the things of wisdom and knowledge; for thus they are gifts of the Holy Ghost, as stated above (Question [68], Articles [1],4). But they are numbered amongst the gratuitous graces, inasmuch as they imply such a fullness of knowledge and wisdom that a man may not merely think aright of Divine things, but may instruct others and overpower adversaries. Hence it is significant that it is the "word" of wisdom and the "word" of knowledge that are placed in the gratuitous graces, since, as Augustine says (De Trin. xiv, 1), "It is one thing merely to know what a man must believe in order to reach everlasting life, and another thing to know how this may benefit the godly and may be defended against the ungodly."

Whether gratuitous grace is nobler than sanctifying grace?


Objection: 1. It would seem that gratuitous grace is nobler than sanctifying grace. For "the people's good is better than the individual good," as the Philosopher says (Ethic. i, 2). Now sanctifying grace is ordained to the good of one man alone, whereas gratuitous grace is ordained to the common good of the whole Church, as stated above (Articles [1],4). Hence gratuitous grace is nobler than sanctifying grace.
Further, it is a greater power that is able to act upon another, than that which is confined to itself, even as greater is the brightness of the body that can illuminate other bodies, than of that which can only shine but cannot illuminate; and hence the Philosopher says (Ethic. v, 1) "that justice is the most excellent of the virtues," since by it a man bears himself rightly towards others. But by sanctifying grace a man is perfected only in himself; whereas by gratuitous grace a man works for the perfection of others. Hence gratuitous grace is nobler than sanctifying grace.
Further, what is proper to the best is nobler than what is common to all; thus to reason, which is proper to man is nobler than to feel, which is common to all animals. Now sanctifying grace is common to all members of the Church, but gratuitous grace is the proper gift of the more exalted members of the Church. Hence gratuitous grace is nobler than sanctifying grace.

On the contrary
The Apostle (1Co 12,31), having enumerated the gratuitous graces adds: "And I shew unto you yet a more excellent way"; and as the sequel proves he is speaking of charity, which pertains to sanctifying grace. Hence sanctifying grace is more noble than gratuitous grace.
I answer that The higher the good to which a virtue is ordained, the more excellent is the virtue. Now the end is always greater than the means. But sanctifying grace ordains a man immediately to a union with his last end, whereas gratuitous grace ordains a man to what is preparatory to the end; i.e. by prophecy and miracles and so forth, men are induced to unite themselves to their last end. And hence sanctifying grace is nobler than gratuitous grace.

Reply to Objection: 1.
As the Philosopher says (Metaph. xii, text. 52), a multitude, as an army, has a double good; the first is in the multitude itself, viz. the order of the army; the second is separate from the multitude, viz. the good of the leader---and this is better good, since the other is ordained to it. Now gratuitous grace is ordained to the common good of the Church, which is ecclesiastical order, whereas sanctifying grace is ordained to the separate common good, which is God. Hence sanctifying grace is the nobler.
If gratuitous grace could cause a man to have sanctifying grace, it would follow that the gratuitous grace was the nobler; even as the brightness of the sun that enlightens is more excellent than that of an object that is lit up. But by gratuitous grace a man cannot cause another to have union with God, which he himself has by sanctifying grace; but he causes certain dispositions towards it. Hence gratuitous grace needs not to be the more excellent, even as in fire, the heat, which manifests its species whereby it produces heat in other things, is not more noble than its substantial form.
Feeling is ordained to reason, as to an end; and thus, to reason is nobler. But here it is the contrary; for what is proper is ordained to what is common as to an end. Hence there is no comparison.



We must now consider the cause of grace; and under this head there are five points of inquiry:

(1) Whether God alone is the efficient cause of grace?

(2) Whether any disposition towards grace is needed on the part of the recipient, by an act of free-will?

(3) Whether such a disposition can make grace follow of necessity?

(4) Whether grace is equal in all?

(5) Whether anyone may know that he has grace?

Whether God alone is the cause of grace?

Objection: 1. It would seem that God alone is not the cause of grace. For it is written (
Jn 1,17): "Grace and truth came by Jesus Christ." Now, by the name of Jesus Christ is understood not merely the Divine Nature assuming, but the created nature assumed. Therefore a creature may be the cause of grace.
2. Further, there is this difference between the sacraments of the New Law and those of the Old, that the sacraments of the New Law cause grace, whereas the sacraments of the Old Law merely signify it. Now the sacraments of the New Law are certain visible elements. Therefore God is not the only cause of grace.
Further, according to Dionysius (Coel. Hier. iii, iv, vii, viii), "Angels cleanse, enlighten, and perfect both lesser angels and men." Now the rational creature is cleansed, enlightened, and perfected by grace. Therefore God is not the only cause of grace.

On the contrary
It is written (Ps 83,12): "The Lord will give grace and glory."
I answer that Nothing can act beyond its species, since the cause must always be more powerful than its effect. Now the gift of grace surpasses every capability of created nature, since it is nothing short of a partaking of the Divine Nature, which exceeds every other nature. And thus it is impossible that any creature should cause grace. For it is as necessary that God alone should deify, bestowing a partaking of the Divine Nature by a participated likeness, as it is impossible that anything save fire should enkindle.

Reply to Objection: 1.
Christ's humanity is an "organ of His Godhead," as Damascene says (De Fide Orth. iii, 19). Now an instrument does not bring forth the action of the principal agent by its own power, but in virtue of the principal agent. Hence Christ's humanity does not cause grace by its own power, but by virtue of the Divine Nature joined to it, whereby the actions of Christ's humanity are saving actions.
As in the person of Christ the humanity causes our salvation by grace, the Divine power being the principal agent, so likewise in the sacraments of the New Law, which are derived from Christ, grace is instrumentally caused by the sacraments, and principally by the power of the Holy Ghost working in the sacraments, according to Jn 3,5: "Unless a man be born again of water and the Holy Ghost he cannot enter into the kingdom of God."
3. Angels cleanse, enlighten, and perfect angels or men, by instruction, and not by justifying them through grace. Hence Dionysius says (Coel. Hier. vii) that "this cleansing and enlightenment and perfecting is nothing else than the assumption of Divine knowledge."

Whether any preparation and disposition for grace is required on man's part?


Objection: 1. It would seem that no preparation or disposition for grace is required on man's part, since, as the Apostle says (
Rm 4,4), "To him that worketh, the reward is not reckoned according to grace, but according to debt." Now a man's preparation by free-will can only be through some operation. Hence it would do away with the notion of grace.
2. Further, whoever is going on sinning, is not preparing himself to have grace. But to some who are going on sinning grace is given, as is clear in the case of Paul, who received grace whilst he was "breathing our threatenings and slaughter against the disciples of the Lord" (Ac 9,1). Hence no preparation for grace is required on man's part.
3. Further, an agent of infinite power needs no disposition in matter, since it does not even require matter, as appears in creation, to which grace is compared, which is called "a new creature" (Ga 6,15). But only God, Who has infinite power, causes grace, as stated above (Article [1]). Hence no preparation is required on man's part to obtain grace.

On the contrary It is written (Am 4,12): "Be prepared to meet thy God, O Israel," and (1S 7,3): "Prepare your hearts unto the Lord."
I answer that As stated above (Question [111], Article [2]), grace is taken in two ways: first, as a habitual gift of God. Secondly, as a help from God, Who moves the soul to good. Now taking grace in the first sense, a certain preparation of grace is required for it, since a form can only be in disposed matter. But if we speak of grace as it signifies a help from God to move us to good, no preparation is required on man's part, that, as it were, anticipates the Divine help, but rather, every preparation in man must be by the help of God moving the soul to good. And thus even the good movement of the free-will, whereby anyone is prepared for receiving the gift of grace is an act of the free-will moved by God. And thus man is said to prepare himself, according to Pr 16,1: "It is the part of man to prepare the soul"; yet it is principally from God, Who moves the free-will. Hence it is said that man's will is prepared by God, and that man's steps are guided by God.

Reply to Objection: 1. A certain preparation of man for grace is simultaneous with the infusion of grace; and this operation is meritorious, not indeed of grace, which is already possessed---but of glory which is not yet possessed. But there is another imperfect preparation, which sometimes precedes the gift of sanctifying grace, and yet it is from God's motion. But it does not suffice for merit, since man is not yet justified by grace, and merit can only arise from grace, as will be seen further on (Question [114], Article [2]).
Since a man cannot prepare himself for grace unless God prevent and move him to good, it is of no account whether anyone arrive at perfect preparation instantaneously, or step by step. For it is written (Si 11,23): "It is easy in the eyes of God on a sudden to make the poor man rich." Now it sometimes happens that God moves a man to good, but not perfect good, and this preparation precedes grace. But He sometimes moves him suddenly and perfectly to good, and man receives grace suddenly, according to Jn 6,45: "Every one that hath heard of the Father, and hath learned, cometh to Me." And thus it happened to Paul, since, suddenly when he was in the midst of sin, his heart was perfectly moved by God to hear, to learn, to come; and hence he received grace suddenly.
3. An agent of infinite power needs no matter or disposition of matter, brought about by the action of something else; and yet, looking to the condition of the thing caused, it must cause, in the thing caused, both the matter and the due disposition for the form. So likewise, when God infuses grace into a soul, no preparation is required which He Himself does not bring about.

Whether grace is necessarily given to whoever prepares himself for it, or to whoever does what he can?


Objection: 1. It would seem that grace is necessarily given to whoever prepares himself for grace, or to whoever does what he can, because, on
Rm 5,1, "Being justified . . . by faith, let us have peace," etc. the gloss says: "God welcomes whoever flies to Him, otherwise there would be injustice with Him." But it is impossible for injustice to be with God. Therefore it is impossible for God not to welcome whoever flies to Him. Hence he receives grace of necessity.
2. Further, Anselm says (De Casu Diaboli. iii) that the reason why God does not bestow grace on the devil, is that he did not wish, nor was he prepared, to receive it. But if the cause be removed, the effect must needs be removed also. Therefore, if anyone is willing to receive grace it is bestowed on them of necessity.
Further, good is diffusive of itself, as appears from Dionysius (Div. Nom. iv). Now the good of grace is better than the good of nature. Hence, since natural forms necessarily come to disposed matter, much more does it seem that grace is necessarily bestowed on whoever prepares himself for grace.

On the contrary
Man is compared to God as clay to the potter, according to Jr 18,6: "As clay is in the hand of the potter, so are you in My hand." But however much the clay is prepared, it does not necessarily receive its shape from the potter. Hence, however much a man prepares himself, he does not necessarily receive grace from God.
I answer that As stated above (Article [2]), man's preparation for grace is from God, as Mover, and from the free-will, as moved. Hence the preparation may be looked at in two ways: first, as it is from free-will, and thus there is no necessity that it should obtain grace, since the gift of grace exceeds every preparation of human power. But it may be considered, secondly, as it is from God the Mover, and thus it has a necessity---not indeed of coercion, but of infallibility---as regards what it is ordained to by God, since God's intention cannot fail, according to the saying of Augustine in his book on the Predestination of the Saints (De Dono Persev. xiv) that "by God's good gifts whoever is liberated, is most certainly liberated." Hence if God intends, while moving, that the one whose heart He moves should attain to grace, he will infallibly attain to it, according to Jn 6,45: "Every one that hath heard of the Father, and hath learned, cometh to Me."

Reply to Objection: 1. This gloss is speaking of such as fly to God by a meritorious act of their free-will, already "informed" with grace; for if they did not receive grace, it would be against the justice which He Himself established. Or if it refers to the movement of free-will before grace, it is speaking in the sense that man's flight to God is by a Divine motion, which ought not, in justice, to fail.
The first cause of the defect of grace is on our part; but the first cause of the bestowal of grace is on God's according to Os 13,9: "Destruction is thy own, O Israel; thy help is only in Me."
3. Even in natural things, the form does not necessarily ensue the disposition of the matter, except by the power of the agent that causes the disposition.

Whether grace is greater in one than in another?


Objection: 1. It would seem that grace is not greater in one than in another. For grace is caused in us by the Divine love, as stated above (Question [110], Article [1]). Now it is written (
Sg 6,8): "He made the little and the great and He hath equally care of all." Therefore all obtain grace from Him equally.
2. Further, whatever is the greatest possible, cannot be more or less. But grace is the greatest possible, since it joins us with our last end. Therefore there is no greater or less in it. Hence it is not greater in one than in another.
Further, grace is the soul's life, as stated above (Question [110], Article [1], ad 2). But there is no greater or less in life. Hence, neither is there in grace.

On the contrary
It is written (Ep 4,7): "But to every one of us is given grace according to the measure of the giving of Christ." Now what is given in measure, is not given to all equally. Hence all have not an equal grace.
I answer that As stated above (Question [52], Articles [1],2; Question [56], Articles [1],2), habits can have a double magnitude: one, as regards the end or object, as when a virtue is said to be more noble through being ordained to a greater good; the other on the part of the subject, which more or less participates in the habit inhering to it.Now as regards the first magnitude, sanctifying grace cannot be greater or less, since, of its nature, grace joins man to the Highest Good, which is God. But as regards the subject, grace can receive more or less, inasmuch as one may be more perfectly enlightened by grace than another. And a certain reason for this is on the part of him who prepares himself for grace; since he who is better prepared for grace, receives more grace. Yet it is not here that we must seek the first cause of this diversity, since man prepares himself, only inasmuch as his free-will is prepared by God. Hence the first cause of this diversity is to be sought on the part of the God, Who dispenses His gifts of grace variously, in order that the beauty and perfection of the Church may result from these various degree; even as He instituted the various conditions of things, that the universe might be perfect. Hence after the Apostle had said (Ep 4,7): "To every one of us is given grace according to the measure of the giving of Christ," having enumerated the various graces, he adds (Ep 4,12): "For the perfecting of the saints . . . for the edifying of the body of Christ."

Reply to Objection: 1. The Divine care may be looked at in two ways: first, as regards the Divine act, which is simple and uniform; and thus His care looks equally to all, since by one simple act He administers great things and little. But, "secondly," it may be considered in those things which come to be considered by the Divine care; and thus, inequality is found, inasmuch as God by His care provides greater gifts to some, and lesser gifts for others.
This objection is based on the first kind of magnitude of grace; since grace cannot be greater by ordaining to a greater good, but inasmuch as it more or less ordains to a greater or less participation of the same good. For there may be diversity of intensity and remissness, both in grace and in final glory as regards the subjects' participation.
Natural life pertains to man's substance, and hence cannot be more or less; but man partakes of the life of grace accidentally, and hence man may possess it more or less.

Whether man can know that he has grace?


Objection: 1. It would seem that man can know that he has grace. For grace by its physical reality is in the soul. Now the soul has most certain knowledge of those things that are in it by their physical reality, as appears from Augustine (Gn ad lit. xii, 31). Hence grace may be known most certainly by one who has grace.
Further, as knowledge is a gift of God, so is grace. But whoever receives knowledge from God, knows that he has knowledge, according to Sg 7,17: The Lord "hath given me the true knowledge of the things that are." Hence, with equal reason, whoever receives grace from God, knows that he has grace.
3. Further, light is more knowable than darkness, since, according to the Apostle (Ep 5,13), "all that is made manifest is light," Now sin, which is spiritual darkness, may be known with certainty by one that is in sin. Much more, therefore, may grace, which is spiritual light, be known.
4. Further, the Apostle says (1Co 2,12): "Now we have received not the Spirit of this world, but the Spirit that is of God; that we may know the things that are given us from God." Now grace is God's first gift. Hence, the man who receives grace by the Holy Spirit, by the same Holy Spirit knows the grace given to him.
5. Further, it was said by the Lord to Abraham (Gn 22,12): "Now I know that thou fearest God," i.e. "I have made thee know." Now He is speaking there of chaste fear, which is not apart from grace. Hence a man may know that he has grace.

On the contrary It is written (Qo 9,1): "Man knoweth not whether he be worthy of love or hatred." Now sanctifying grace maketh a man worthy of God's love. Therefore no one can know whether he has sanctifying grace.
I answer that There are three ways of knowing a thing: First, by revelation, and thus anyone may know that he has grace, for God by a special privilege reveals this at times to some, in order that the joy of safety may begin in them even in this life, and that they may carry on toilsome works with greater trust and greater energy, and may bear the evils of this present life, as when it was said to Paul (2Co 12,9): "My grace is sufficient for thee."Secondly, a man may, of himself, know something, and with certainty; and in this way no one can know that he has grace. For certitude about a thing can only be had when we may judge of it by its proper principle. Thus it is by undemonstrable universal principles that certitude is obtained concerning demonstrative conclusions. Now no one can know he has the knowledge of a conclusion if he does not know its principle. But the principle of grace and its object is God, Who by reason of His very excellence is unknown to us, according to Jb 36,26: "Behold God is great, exceeding our knowledge." And hence His presence in us and His absence cannot be known with certainty, according to Jb 9,11: "If He come to me, I shall not see Him; if He depart I shall not understand." And hence man cannot judge with certainty that he has grace, according to 1Co 4,3-4: "But neither do I judge my own self . . . but He that judgeth me is the Lord."Thirdly, things are known conjecturally by signs; and thus anyone may know he has grace, when he is conscious of delighting in God, and of despising worldly things, and inasmuch as a man is not conscious of any mortal sin. And thus it is written (Ap 2,17): "To him that overcometh I will give the hidden manna . . . which no man knoweth, but he that receiveth it," because whoever receives it knows, by experiencing a certain sweetness, which he who does not receive it, does not experience. Yet this knowledge is imperfect; hence the Apostle says (1Co 4,4): "I am not conscious to myself of anything, yet am I not hereby justified," since, according to Ps 18,13: "Who can understand sins? From my secret ones cleanse me, O Lord, and from those of others spare Thy servant."

Reply to Objection: 1. Those things which are in the soul by their physical reality, are known through experimental knowledge; in so far as through acts man has experience of their inward principles: thus when we wish, we perceive that we have a will; and when we exercise the functions of life, we observe that there is life in us.
It is an essential condition of knowledge that a man should have certitude of the objects of knowledge; and again, it is an essential condition of faith that a man should be certain of the things of faith, and this, because certitude belongs to the perfection of the intellect, wherein these gifts exist. Hence, whoever has knowledge or faith is certain that he has them. But it is otherwise with grace and charity and such like, which perfect the appetitive faculty.
Sin has for its principal object commutable good, which is known to us. But the object or end of grace is unknown to us on account of the greatness of its light, according to 1Tm 6,16: "Who . . . inhabiteth light inaccessible."
4. The Apostle is here speaking of the gifts of glory, which have been given to us in hope, and these we know most certainly by faith, although we do not know for certain that we have grace to enable us to merit them. Or it may be said that he is speaking of the privileged knowledge, which comes of revelation. Hence he adds (1Co 2,10): "But to us God hath revealed them by His Spirit."
5.What was said to Abraham may refer to experimental knowledge which springs from deeds of which we are cognizant. For in the deed that Abraham had just wrought, he could know experimentally that he had the fear of God. Or it may refer to a revelation.

Summa Th. I-II EN Qu.111 a.3