In the Orthodox liturgical calendar, today is Forgiveness Sunday, which fittingly follows last week's Judgment Sunday. So I thought I'd put up what Thomas Aquinas says about Christ's passion and forgiveness of sins. The standard caveats apply -- it's all rough. The Latin is here. The Dominican Fathers translation is here.
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We proceed to the first in this way. It seems that we are not freed from sin by the passion of Christ. For to free from sin is proper to God according to Isaiah XLIII, 'I am He who blots out your iniquities for my sake.' But Christ does not suffer insofar as He is God, but insofar as He is man. Therefore the passion of Christ did not free us from sin.
Further, the corporeal does not act on the spiritual. But the passion of Christ is corporeal, whereas sin is in the soul, which is a spiritual creature. Therefore the passion of Christ could not cleanse us from sin.
Further, no one can be freed from sin that they have not yet committed, but will be committed afterward. Since, therefore, many sins have been committed after the passion of Christ, and are committed daily, it seems that we are not freed from sin through the passion of Christ.
Further, when a sufficient cause is posited, nothing else is required to induce the effect. But other things are required for remission of sins, like baptism and penance. Therefore it seems that the passion of Christ is not a sufficient cause of the remission of sins.
Further, Proverbs X says, "Charity covers all sins"; and XV says, "Through mercy and faith sins are purged." But there are many other things in which we have faith, and which provoke charity. Therefore the passion of Christ is not the proper cause of remission of sins.
But on the other hand is what Apoc. I says: "He loved us, and washed away our sins in his blood."
I reply that it must be said that the passion of Christ is the proper cause of remission of sins, in three ways.
First, by way of provoking charity. Because, as the apostle says, Rom. V, "God commends his charity in us, in that, when we were enemies, Christ died for us. But it is through charity that we procure pardon of sins, as is said in Luke VII, "Many sins are forgiven her because she has loved much."
Second, the passion of Christ causes remission of sins by way of redemption. For since he is our head, through his passion, which he endured through charity and obedience, he freed us, as his members, from sin, as it were by the price of his passion; just as if a man were through some meritorious work of his hand to redeem himself from sins committed by his feet. For just as the natural body is one, constituted of many diverse members, so the whole Church, which is the mystical body of Christ, counted as one person with its head, who is Christ.
Third, by way of efficacy, inasmuch as the flesh, according to which Christ endured the passion, is the instrument of the divinity, so that his passions and actions work as having a divine power for expelling sin.
To the first, then, it must be said that, although Christ did not suffer insofar as He was God, nonetheless his flesh is the instrument of the divinity. And from this his passion has a sort of divine power for expelling sin, as was said.
To the second it must be said that the passion of Christ, although it is corporeal, nonetheless derives a sort of spiritual power from the divinity, to which the flesh is united as an instrument. According to this power Christ's passion is the cause of the remission of sins.
To the third it must be said that Christ causally freed us from sins by his passion; that is. by instituting the cause of our liberation, from which all sins, whether past or present or future, could be remitted, as if a doctor were to make a medicine by which all diseases could be cured, even in the future.
To the fourth it must be said that, as Christ's passion came before, as a sort of universal cause for the remission of sins, as was said, it is necessary for it to be applied to singular [cases] for the deletion of each one's own sins. But this is done by baptism and penance and the other sacraments, which have power from the passion of Christ, as is shown below.
To the fifth it must be said that Christ's passion is applied even by faith to to producing of its fruits, as is said in Rom. III, "Whom God has proposed to be a propitiator through faith in His blood." But faith through which we are cleansed from sin is not an unformed faith, which is able to be even with sin, but is a faith given form by charity, that the passion of Christ may be applied to us not only with regard to the intellect, but also with regard to the affect. And even in this way sins are diminished only through the power of Christ's passion.
