Whether the forgiveness of mortal sin is an effect of this sacrament?
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.
Objection 2: Further, this sacrament, like Baptism, works by the power of Christ's Passion. But mortal sins are forgiven by Baptism, as stated above (Q 69, A 1). 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."
Objection 3: Further, grace is bestowed through this sacrament, as stated above (A 1). But by grace a man is justified from mortal sins, according to Rom. 3:24: "Being justified freely by His grace." Therefore mortal sins are forgiven by this sacrament.
On the contrary, It is written (1 Cor. 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.
Reply to Objection 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.
Reply to Objection 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.
III · Q. 79, Art. 4: Whether venial sins are forgiven through this sacrament?
Whether venial sins are forgiven through this sacrament?
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, Q 88, AA 1,2; SS, Q 24, A 10. Therefore, since contrary is taken away by its contrary, it seems that venial sins are not forgiven by this sacrament.
Objection 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 1 Jn. 1:8: "If we say that we have no sin, we deceive ourselves." Therefore no venial sin is forgiven by this sacrament.
Objection 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, Q 24, A 10. 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.
Reply to Objection 1: 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.
Reply to Objection 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.