Summa Th. III EN Qu.79 a.1
Objection: 1. It seems that grace is not bestowed through this sacrament. For this sacrament is spiritual nourishment. But nourishment is only given to the living. Therefore since the spiritual life is the effect of grace, this sacrament belongs only to one in the state of grace. Therefore grace is not bestowed through this sacrament for it to be had in the first instance. In like manner neither is it given so as grace may be increased, because spiritual growth belongs to the sacrament of Confirmation, as stated above (Question , Article ). Consequently, grace is not bestowed through this sacrament.
2. Further, this sacrament is given as a spiritual refreshment. But spiritual refreshment seems to belong to the use of grace rather than to its bestowal. Therefore it seems that grace is not given through this sacrament.
3. Further, as was said above (Question , Article ), "Christ's body is offered up in this sacrament for the salvation of the body, and His blood for that of the soul." Now it is not the body which is the subject of grace, but the soul, as was shown in the FS, Question , Article . Therefore grace is not bestowed through this sacrament, at least so far as the body is concerned.
On the contrary Our Lord says (Jn 6,52): "The bread which I will give, is My flesh for the life of the world." But the spiritual life is the effect of grace. Therefore grace is bestowed through this sacrament.
I answer that The effect of this sacrament ought to be considered, First of all and principally, from what is contained in this sacrament, which is Christ; Who, just as by coming into the world, He visibly bestowed the life of grace upon the world, according to Jn 1,17: "Grace and truth came by Jesus Christ," so also, by coming sacramentally into man causes the life of grace, according to Jn 6,58: "He that eateth Me, the same also shall live by Me." Hence Cyril says on Lc 22,19: "God's life-giving Word by uniting Himself with His own flesh, made it to be productive of life. For it was becoming that He should be united somehow with bodies through His sacred flesh and precious blood, which we receive in a life-giving blessing in the bread and wine."Secondly, it is considered on the part of what is represented by this sacrament, which is Christ's Passion, as stated above (Question , Article ; Question , Article , ad 1). And therefore this sacrament works in man the effect which Christ's Passion wrought in the world. Hence, Chrysostom says on the words, "Immediately there came out blood and water" (Jn 19,34): "Since the sacred mysteries derive their origin from thence, when you draw nigh to the awe-inspiring chalice, so approach as if you were going to drink from Christ's own side." Hence our Lord Himself says (Mt 26,28): "This is My blood . . . which shall be shed for many unto the remission of sins."Thirdly, the effect of this sacrament is considered from the way in which this sacrament is given; for it is given by way of food and drink. And therefore this sacrament does for the spiritual life all that material food does for the bodily life, namely, by sustaining, giving increase, restoring, and giving delight. Accordingly, Ambrose says (De Sacram. v): "This is the bread of everlasting life, which supports the substance of our soul." And Chrysostom says (Hom. xlvi in Joan.): "When we desire it, He lets us feel Him, and eat Him, and embrace Him." And hence our Lord says (Jn 6,56): "My flesh is meat indeed, and My blood is drink indeed."Fourthly, the effect of this sacrament is considered from the species under which it is given. Hence Augustine says (Tract. xxvi in Joan.): "Our Lord betokened His body and blood in things which out of many units are made into some one whole: for out of many grains is one thing made," viz. bread; "and many grapes flow into one thing," viz. wine. And therefore he observes elsewhere (Tract. xxvi in Joan.): "O sacrament of piety, O sign of unity, O bond of charity!"And since Christ and His Passion are the cause of grace. and since spiritual refreshment, and charity cannot be without grace, it is clear from all that has been set forth that this sacrament bestows grace.
Reply to Objection: 1. This sacrament has of itself the power of bestowing grace; nor does anyone possess grace before receiving this sacrament except from some desire thereof; from his own desire, as in the case of the adult. or from the Church's desire in the case of children, as stated above (Question , Article ). Hence it is due to the efficacy of its power, that even from desire thereof a man procures grace whereby he is enabled to lead the spiritual life. It remains, then, that when the sacrament itself is really received, grace is increased, and the spiritual life perfected: yet in different fashion from the sacrament of Confirmation, in which grace is increased and perfected for resisting the outward assaults of Christ's enemies. But by this sacrament grace receives increase, and the spiritual life is perfected, so that man may stand perfect in himself by union with God.
2. This sacrament confers grace spiritually together with the virtue of charity. Hence Damascene (De Fide Orth. iv) compares this sacrament to the burning coal which Isaias saw (Is 6,6): "For a live ember is not simply wood, but wood united to fire; so also the bread of communion is not simple bread but bread united with the Godhead." But as Gregory observes in a Homily for Pentecost, "God's love is never idle; for, wherever it is it does great works." And consequently through this sacrament, as far as its power is concerned, not only is the habit of grace and of virtue bestowed, but it is furthermore aroused to act, according to 2Co 5,14: "The charity of Christ presseth us." Hence it is that the soul is spiritually nourished through the power of this sacrament, by being spiritually gladdened, and as it were inebriated with the sweetness of the Divine goodness, according to Cant 5:1: "Eat, O friends, and drink, and be inebriated, my dearly beloved."
3. Because the sacraments operate according to the similitude by which they signify, therefore by way of assimilation it is said that in this sacrament "the body is offered for the salvation of the body, and the blood for the salvation of the soul," although each works for the salvation of both, since the entire Christ is under each, as stated above (Question , Article ). And although the body is not the immediate subject of grace, still the effect of grace flows into the body while in the present life we present "our [Vulg.: 'your'] members" as "instruments of justice unto God" (Rm 6,13), and in the life to come our body will share in the incorruption and the glory of the soul.
Objection: 1. It seems that the attaining of glory is not an effect of this sacrament. For an effect is proportioned to its cause. But this sacrament belongs to "wayfarers" [viatoribus], and hence it is termed "Viaticum." Since, then, wayfarers are not yet capable of glory, it seems that this sacrament does not cause the attaining of glory.
2. Further, given sufficient cause, the effect follows. But many take this sacrament who will never come to glory, as Augustine declares (De Civ. Dei xxi). Consequently, this sacrament is not the cause of attaining unto glory.
3. Further, the greater is not brought about by the lesser, for nothing acts outside its species. But it is the lesser thing to receive Christ under a strange species, which happens in this sacrament, than to enjoy Him in His own species, which belongs to glory. Therefore this sacrament does not cause the attaining of glory.
On the contrary It is written (Jn 6,52): "If any man eat of this bread, he shall live for ever." But eternal life is the life of glory. Therefore the attaining of glory is an effect of this sacrament.
I answer that In this sacrament we may consider both that from which it derives its effect, namely, Christ contained in it, as also His Passion represented by it; and that through which it works its effect, namely, the use of the sacrament, and its species.Now as to both of these it belongs to this sacrament to cause the attaining of eternal life. Because it was by His Passion that Christ opened to us the approach to eternal life, according to He 9,15: "He is the Mediator of the New Testament; that by means of His death . . . they that are called may receive the promise of eternal inheritance." Accordingly in the form of this sacrament it is said: "This is the chalice of My blood, of the New and Eternal Testament."In like manner the refreshment of spiritual food and the unity denoted by the species of the bread and wine are to be had in the present life, although imperfectly. but perfectly in the state of glory. Hence Augustine says on the words, "My flesh is meat indeed" (Jn 6,56): "Seeing that in meat and drink, men aim at this, that they hunger not nor thirst, this verily nought doth afford save only this meat and drink which maketh them who partake thereof to be immortal and incorruptible, in the fellowship of the saints, where shall be peace, and unity, full and perfect."
Reply to Objection: 1. As Christ's Passion, in virtue whereof this sacrament is accomplished, is indeed the sufficient cause of glory, yet not so that we are thereby forthwith admitted to glory, but we must first "suffer with Him in order that we may also be glorified" afterwards "with Him" (Rm 8,17), so this sacrament does not at once admit us to glory, but bestows on us the power of coming unto glory. And therefore it is called "Viaticum," a figure whereof we read in 1R 19,8: "Elias ate and drank, and walked in the strength of that food forty days and forty nights unto the mount of God, Horeb."
2. Just as Christ's Passion has not its effect in them who are not disposed towards it as they should be, so also they do not come to glory through this sacrament who receive it unworthily. Hence Augustine (Tract. xxvi in Joan.), expounding the same passage, observes: "The sacrament is one thing, the power of the sacrament another. Many receive it from the altar . . . and by receiving" . . . die . . . Eat, then, spiritually the heavenly "bread, bring innocence to the altar." It is no wonder, then, if those who do not keep innocence, do not secure the effect of this sacrament.
3. That Christ is received under another species belongs to the nature of a sacrament, which acts instrumentally. But there is nothing to prevent an instrumental cause from producing a more mighty effect, as is evident from what was said above (Question , Article , ad 3).
Objection: 1. It seems that the forgiveness of mortal sin is an effect of this sacrament. For it is said in one of the Collects (Postcommunion, Pro vivis et defunctis): "May this sacrament be a cleansing from crimes." But mortal sins are called crimes. Therefore mortal sins are blotted out by this sacrament.
2. Further, this sacrament, like Baptism, works by the power of Christ's Passion. But mortal sins are forgiven by Baptism, as stated above (Question , Article ). Therefore they are forgiven likewise by this sacrament, especially since in the form of this sacrament it is said: "Which shall be shed for many unto the forgiveness of sins."
3. Further, grace is bestowed through this sacrament, as stated above (Article ). But by grace a man is justified from mortal sins, according to Rm 3,24: "Being justified freely by His grace." Therefore mortal sins are forgiven by this sacrament.
On the contrary It is written (1Co 11,29): "He that eateth and drinketh unworthily, eateth and drinketh judgment to himself": and a gloss of the same passage makes the following commentary: "He eats and drinks unworthily who is in the state of sin, or who handles (the sacrament) irreverently; and such a one eats and drinks judgment, i.e. damnation, unto himself." Therefore, he that is in mortal sin, by taking the sacrament heaps sin upon sin, rather than obtains forgiveness of his sin.
I answer that The power of this sacrament can be considered in two ways. First of all, in itself: and thus this sacrament has from Christ's Passion the power of forgiving all sins, since the Passion is the fount and cause of the forgiveness of sins.Secondly, it can be considered in comparison with the recipient of the sacrament, in so far as there is, or is not, found in him an obstacle to receiving the fruit of this sacrament. Now whoever is conscious of mortal sin, has within him an obstacle to receiving the effect of this sacrament; since he is not a proper recipient of this sacrament, both because he is not alive spiritually, and so he ought not to eat the spiritual nourishment, since nourishment is confined to the living; and because he cannot be united with Christ, which is the effect of this sacrament, as long as he retains an attachment towards mortal sin. Consequently, as is said in the book De Eccles. Dogm.: "If the soul leans towards sin, it is burdened rather than purified from partaking of the Eucharist." Hence, in him who is conscious of mortal sin, this sacrament does not cause the forgiveness of sin.Nevertheless this sacrament can effect the forgiveness of sin in two ways. First of all, by being received, not actually, but in desire; as when a man is first justified from sin. Secondly, when received by one in mortal sin of which he is not conscious, and for which he has no attachment; since possibly he was not sufficiently contrite at first, but by approaching this sacrament devoutly and reverently he obtains the grace of charity, which will perfect his contrition and bring forgiveness of sin.
Reply to Objection: 1. We ask that this sacrament may be the "cleansing of crimes," or of those sins of which we are unconscious, according to Ps 18,13: "Lord, cleanse me from my hidden sins"; or that our contrition may be perfected for the forgiveness of our sins; or that strength be bestowed on us to avoid sin.
2. Baptism is spiritual generation, which is a transition from spiritual non-being into spiritual being, and is given by way of ablution. Consequently, in both respects he who is conscious of mortal sin does not improperly approach Baptism. But in this sacrament man receives Christ within himself by way of spiritual nourishment, which is unbecoming to one that lies dead in his sins. Therefore the comparison does not hold good.
3. Grace is the sufficient cause of the forgiveness of mortal sin; yet it does not forgive sin except when it is first bestowed on the sinner. But it is not given so in this sacrament. Hence the argument does not prove.
Objection: 1. It seems that venial sins are not forgiven by this sacrament, because this is the "sacrament of charity," as Augustine says (Tract. xxvi in Joan.). But venial sins are not contrary to charity, as was shown in the FS, Question , Articles ,2; SS, Question , Article . Therefore, since contrary is taken away by its contrary, it seems that venial sins are not forgiven by this sacrament.
2. Further, if venial sins be forgiven by this sacrament, then all of them are forgiven for the same reason as one is. But it does not appear that all are forgiven, because thus one might frequently be without any venial sin, against what is said in 1Jn 1,8: "If we say that we have no sin, we deceive ourselves." Therefore no venial sin is forgiven by this sacrament.
3. Further, contraries mutually exclude each other. But venial sins do not forbid the receiving of this sacrament: because Augustine says on the words, "If any man eat of it he shall [Vulg.: 'may'] not die for ever" (Jn 6,50): "Bring innocence to the altar: your sins, though they be daily . . . let them not be deadly." Therefore neither are venial sins taken away by this sacrament.
On the contrary Innocent III says (De S. Alt. Myst. iv) that this sacrament "blots out venial sins, and wards off mortal sins."
I answer that Two things may be considered in this sacrament, to wit, the sacrament itself, and the reality of the sacrament: and it appears from both that this sacrament has the power of forgiving venial sins. For this sacrament is received under the form of nourishing food. Now nourishment from food is requisite for the body to make good the daily waste caused by the action of natural heat. But something is also lost daily of our spirituality from the heat of concupiscence through venial sins, which lessen the fervor of charity, as was shown in the SS, Question , Article . And therefore it belongs to this sacrament to forgive venial sins. Hence Ambrose says (De Sacram. v) that this daily bread is taken "as a remedy against daily infirmity."The reality of this sacrament is charity, not only as to its habit, but also as to its act, which is kindled in this sacrament; and by this means venial sins are forgiven. Consequently, it is manifest that venial sins are forgiven by the power of this sacrament.
Reply to Objection: 1. Venial sins, although not opposed to the habit of charity, are nevertheless opposed to the fervor of its act, which act is kindled by this sacrament; by reason of which act venial sins are blotted out.
2. The passage quoted is not to be understood as if a man could not at some time be without all guilt of venial sin: but that the just do not pass through this life without committing venial sins.
3. The power of charity, to which this sacrament belongs, is greater than that of venial sins: because charity by its act takes away venial sins, which nevertheless cannot entirely hinder the act of charity. And the same holds good of this sacrament.
Objection: 1. It seems that the entire punishment due to sin is forgiven through this sacrament. For through this sacrament man receives the effect of Christ's Passion within himself as stated above (Articles ,2), just as he does through Baptism. But through Baptism man receives forgiveness of all punishment, through the virtue of Christ's Passion, which satisfied sufficiently for all sins, as was explained above (Question , Article ). Therefore it seems the whole debt of punishment is forgiven through this sacrament.
2. Further, Pope Alexander I says (Ep ad omnes orth.): "No sacrifice can be greater than the body and the blood of Christ." But man satisfied for his sins by the sacrifices of the old Law: for it is written (Lv 4,5): "If a man shall sin, let him offer" (so and so) "for his sin, and it shall be forgiven him." Therefore this sacrament avails much more for the forgiveness of all punishment.
3. Further, it is certain that some part of the debt of punishment is forgiven by this sacrament; for which reason it is sometimes enjoined upon a man, by way of satisfaction, to have masses said for himself. But if one part of the punishment is forgiven, for the same reason is the other forgiven: owing to Christ's infinite power contained in this sacrament. Consequently, it seems that the whole punishment can be taken away by this sacrament.
On the contrary In that case no other punishment would have to be enjoined; just as none is imposed upon the newly baptized.
I answer that This sacrament is both a sacrifice and a sacrament. it has the nature of a sacrifice inasmuch as it is offered up; and it has the nature of a sacrament inasmuch as it is received. And therefore it has the effect of a sacrament in the recipient, and the effect of a sacrifice in the offerer, or in them for whom it is offered.If, then, it be considered as a sacrament, it produces its effect in two ways: first of all directly through the power of the sacrament; secondly as by a kind of concomitance, as was said above regarding what is contained in the sacrament (Question , Articles ,2). Through the power of the sacrament it produces directly that effect for which it was instituted. Now it was instituted not for satisfaction, but for nourishing spiritually through union between Christ and His members, as nourishment is united with the person nourished. But because this union is the effect of charity, from the fervor of which man obtains forgiveness, not only of guilt but also of punishment, hence it is that as a consequence, and by concomitance with the chief effect, man obtains forgiveness of the punishment, not indeed of the entire punishment, but according to the measure of his devotion and fervor.But in so far as it is a sacrifice, it has a satisfactory power. Yet in satisfaction, the affection of the offerer is weighed rather than the quantity of the offering. Hence our Lord says (Mc 12,43, cf. Lc 21,4) of the widow who offered "two mites" that she "cast in more than all." Therefore, although this offering suffices of its own quantity to satisfy for all punishment, yet it becomes satisfactory for them for whom it is offered, or even for the offerers, according to the measure of their devotion, and not for the whole punishment.
Reply to Objection: 1. The sacrament of Baptism is directly ordained for the remission of punishment and guilt: not so the Eucharist, because Baptism is given to man as dying with Christ, whereas the Eucharist is given as by way of nourishing and perfecting him through Christ. Consequently there is no parallel.
2. Those other sacrifices and oblations did not effect the forgiveness of the whole punishment, neither as to the quantity of the thing offered, as this sacrament does, nor as to personal devotion; from which it comes to pass that even here the whole punishment is not taken away.
3. If part of the punishment and not the whole be taken away by this sacrament, it is due to a defect not on the part of Christ's power, but on the part of man's devotion.
Objection: 1. It seems that man is not preserved by this sacrament from future sins. For there are many that receive this sacrament worthily, who afterwards fall into sin. Now this would not happen if this sacrament were to preserve them from future sins. Consequently, it is not an effect of this sacrament to preserve from future sins.
2. Further, the Eucharist is the sacrament of charity, as stated above (Article ). But charity does not seem to preserve from future sins, because it can be lost through sin after one has possessed it, as was stated in the SS, Question , Article . Therefore it seems that this sacrament does not preserve man from sin.
3. Further, the origin of sin within us is "the law of sin, which is in our members," as declared by the Apostle (Rm 7,23). But the lessening of the fomes, which is the law of sin, is set down as an effect not of this sacrament, but rather of Baptism. Therefore preservation from sin is not an effect of this sacrament.
On the contrary our Lord said (Jn 6,50): "This is the bread which cometh down from heaven; that if any man eat of it, he may not die": which manifestly is not to be understood of the death of the body. Therefore it is to be understood that this sacrament preserves from spiritual death, which is through sin.
I answer that Sin is the spiritual death of the soul. Hence man is preserved from future sin in the same way as the body is preserved from future death of the body: and this happens in two ways. First of all, in so far as man's nature is strengthened inwardly against inner decay, and so by means of food and medicine he is preserved from death. Secondly, by being guarded against outward assaults; and thus he is protected by means of arms by which he defends his body.Now this sacrament preserves man from sin in both of these ways. For, first of all, by uniting man with Christ through grace, it strengthens his spiritual life, as spiritual food and spiritual medicine, according to Ps 103,5: "(That) bread strengthens [Vulg.: 'may strengthen'] man's heart." Augustine likewise says (Tract. xxvi in Joan.): "Approach without fear; it is bread, not poison." Secondly, inasmuch as it is a sign of Christ's Passion, whereby the devils are conquered, it repels all the assaults of demons. Hence Chrysostom says (Hom. xlvi in Joan.): "Like lions breathing forth fire, thus do we depart from that table, being made terrible to the devil."
Reply to Objection: 1. The effect of this sacrament is received according to man's condition: such is the case with every active cause in that its effect is received in matter according to the condition of the matter. But such is the condition of man on earth that his free-will can be bent to good or evil. Hence, although this sacrament of itself has the power of preserving from sin, yet it does not take away from man the possibility of sinning.
2. Even charity of itself keeps man from sin, according to Rm 13,10: "The love of our neighbor worketh no evil": but it is due to the mutability of free-will that a man sins after possessing charity, just as after receiving this sacrament.
3. Although this sacrament is not ordained directly to lessen the fomes, yet it does lessen it as a consequence, inasmuch as it increases charity, because, as Augustine says (Question ), "the increase of charity is the lessening of concupiscence." But it directly strengthens man's heart in good; whereby he is also preserved from sin.
Objection: 1. It seems that this sacrament benefits only the recipients. For this sacrament is of the same genus as the other sacraments, being one of those into which that genus is divided. But the other sacraments only benefit the recipients; thus the baptized person alone receives effect of Baptism. Therefore, neither does this sacrament benefit others than the recipients.
2. Further, the effects of this sacrament are the attainment of grace and glory, and the forgiveness of sin, at least of venial sin. If therefore this sacrament were to produce its effects in others besides the recipients, a man might happen to acquire grace and glory and forgiveness of sin without doing or receiving anything himself, through another receiving or offering this sacrament.
3. Further, when the cause is multiplied, the effect is likewise multiplied. If therefore this sacrament benefit others besides the recipients, it would follow that it benefits a man more if he receive this sacrament through many hosts being consecrated in one mass, whereas this is not the Church's custom: for instance, that many receive communion for the salvation of one individual. Consequently, it does not seem that this sacrament benefits anyone but the recipient.
On the contrary Prayer is made for many others during the celebration of this sacrament; which would serve no purpose were the sacrament not beneficial to others. Therefore, this sacrament is beneficial not merely to them who receive it.
I answer that As stated above (Article ), this sacrament is not only a sacrament, but also a sacrifice. For, it has the nature of a sacrifice inasmuch as in this sacrament Christ's Passion is represented, whereby Christ "offered Himself a Victim to God" (Ep 5,2), and it has the nature of a sacrament inasmuch as invisible grace is bestowed in this sacrament under a visible species. So, then, this sacrament benefits recipients by way both of sacrament and of sacrifice, because it is offered for all who partake of it. For it is said in the Canon of the Mass: "May as many of us as, by participation at this Altar, shall receive the most sacred body and blood of Thy Son, be filled with all heavenly benediction and grace."But to others who do not receive it, it is beneficial by way of sacrifice, inasmuch as it is offered for their salvation. Hence it is said in the Canon of the Mass: "Be mindful, O Lord, of Thy servants, men and women . . . for whom we offer, or who offer up to Thee, this sacrifice of praise for themselves and for all their own, for the redemption of their souls, for the hope of their safety and salvation." And our Lord expressed both ways, saying (Mt 26,28, with Lc 22,20): "Which for you," i.e. who receive it, "and for many," i.e. others, "shall be shed unto remission of sins."
Reply to Objection: 1. This sacrament has this in addition to the others, that it is a sacrifice: and therefore the comparison fails.
2. As Christ's Passion benefits all, for the forgiveness of sin and the attaining of grace and glory, whereas it produces no effect except in those who are united with Christ's Passion through faith and charity, so likewise this sacrifice, which is the memorial of our Lord's Passion, has no effect except in those who are united with this sacrament through faith and charity. Hence Augustine says to Renatus (De Anima et ejus origine i): "Who may offer Christ's body except for them who are Christ's members?" Hence in the Canon of the Mass no prayer is made for them who are outside the pale of the Church. But it benefits them who are members, more or less, according to the measure of their devotion.
3. Receiving is of the very nature of the sacrament, but offering belongs to the nature of sacrifice: consequently, when one or even several receive the body of Christ, no help accrues to others. In like fashion even when the priest consecrates several hosts in one mass, the effect of this sacrament is not increased, since there is only one sacrifice; because there is no more power in several hosts than in one, since there is only one Christ present under all the hosts and under one. Hence, neither will any one receive greater effect from the sacrament by taking many consecrated hosts in one mass. But the oblation of the sacrifice is multiplied in several masses, and therefore the effect of the sacrifice and of the sacrament is multiplied.
Objection: 1. It seems that the effect of this sacrament is not hindered by venial sin. For Augustine (Tract. xxvi in Joan.), commenting on Jn 6,52, "If any man eat of this bread," etc., says: "Eat the heavenly bread spiritually; bring innocence to the altar; your sins, though they be daily, let them not be deadly." From this it is evident that venial sins, which are called daily sins, do not prevent spiritual eating. But they who eat spiritually, receive the effect of this sacrament. Therefore, venial sins do not hinder the effect of this sacrament.
2. Further, this sacrament is not less powerful than Baptism. But, as stated above (Question , Articles ,10), only pretense checks the effect of Baptism, and venial sins do not belong to pretense; because according to Sg 1,5: "the Holy Spirit of discipline will flee from the deceitful," yet He is not put to flight by venial sins. Therefore neither do venial sins hinder the effect of this sacrament.
3. Further, nothing which is removed by the action of any cause, can hinder the effect of such cause. But venial sins are taken away by this sacrament. Therefore, they do not hinder its effect.
On the contrary Damascene says (De Fide Orth. iv): "The fire of that desire which is within us, being kindled by the burning coal," i.e. this sacrament, "will consume our sins, and enlighten our hearts, so that we shall be inflamed and made godlike." But the fire of our desire or love is hindered by venial sins, which hinder the fervor of charity, as was shown in the FS, Question , Article ; SS, Question , Article . Therefore venial sins hinder the effect of this sacrament.
I answer that Venial sins can be taken in two ways: first of all as past, secondly as in the act of being committed. Venial sins taken in the first way do not in any way hinder the effect of this sacrament. For it can come to pass that after many venial sins a man may approach devoutly to this sacrament and fully secure its effect. Considered in the second way venial sins do not utterly hinder the effect of this sacrament, but merely in part. For, it has been stated above (Article ), that the effect of this sacrament is not only the obtaining of habitual grace or charity, but also a certain actual refreshment of spiritual sweetness: which is indeed hindered if anyone approach to this sacrament with mind distracted through venial sins; but the increase of habitual grace or of charity is not taken away.
Reply to Objection: 1. He that approaches this sacrament with actual venial sin, eats spiritually indeed, in habit but not in act: and therefore he shares in the habitual effect of the sacrament, but not in its actual effect.
2. Baptism is not ordained, as this sacrament is, for the fervor of charity as its actual effect. Because Baptism is spiritual regeneration, through which the first perfection is acquired, which is a habit or form; but this sacrament is spiritual eating, which has actual delight.
3. This argument deals with past venial sins, which are taken away by this sacrament.
Summa Th. III EN Qu.79 a.1