Augustine on 2 Cor. 5:21

Chapter 41. Christ, Who Was Himself Free from Sin, Was Made Sin for Us, that We Might Be Reconciled to God.

Begotten and conceived, then, without any indulgence of carnal lust, and therefore bringing with Him no original sin, and by the grace of God joined and united in a wonderful and unspeakable way in one person with the Word, the Only-begotten of the Father, a son by nature, not by grace, and therefore having no sin of His own; nevertheless, on account of the likeness of sinful flesh in which He came, He was called sin, that He might be sacrificed to wash away sin. For, under the Old Covenant, sacrifices for sin were called sins.

And He, of whom all these sacrifices were types and shadows, was Himself truly made sin.

Hence the apostle, after saying, We pray you in Christ’s stead, be ye reconciled to God, immediately adds: for He has made Him to be sin for us who knew no sin; that we might be made the righteousness of God in Him.

He does not say, as some incorrect copies read, He who knew no sin did sin for us, as if Christ had Himself sinned for our sakes; but he says, Him who knew no sin, that is, Christ, God, to whom we are to be reconciled, has made to be sin for us, that is, has made Him a sacrifice for our sins, by which we might be reconciled to God.

He, then, being made sin, just as we are made righteousness (our righteousness being not our own, but God’s, not in ourselves, but in Him); He being made sin, not His own, but ours, not in Himself, but in us, showed, by the likeness of sinful flesh in which He was crucified, that though sin was not in Him, yet that in a certain sense He died to sin, by dying in the flesh which was the likeness of sin; and that although He Himself had never lived the old life of sin, yet by His resurrection He typified our new life springing up out of the old death in sin.

Chapter 42. The Sacrament of Baptism Indicates Our Death with Christ to Sin, and Our Resurrection with Him to Newness of Life.

And this is the meaning of the great sacrament of baptism which is solemnized among us, that all who attain to this grace should die to sin, as He is said to have died to sin, because He died in the flesh, which is the likeness of sin; and rising from the font regenerate, as He arose alive from the grave, should begin a new life in the Spirit, whatever may be the age of the body?

Chapter 43. Baptism and the Grace Which It Typifies are Open to All, Both Infants and Adults.

For from the infant newly born to the old man bent with age, as there is none shut out from baptism, so there is none who in baptism does not die to sin. But infants die only to original sin; those who are older die also to all the sins which their evil lives have added to the sin which they brought with them.

Chapter 44. In Speaking of Sin, the Singular Number is Often Put for the Plural, and the Plural for the Singular.

But even these latter are frequently said to die to sin, though undoubtedly they die not to one sin, but to all the numerous actual sins they have committed in thought, word, or deed:

for the singular number is often put for the plural, as when the poet says, They fill its belly with the armed soldier, though in the case here referred to there were many soldiers concerned. And we read in our own Scriptures: Pray to the Lord, that He take away the serpent from us. He does not say serpents though the people were suffering from many; and so in other cases.

When, on the other hand, the original sin is expressed in the plural number, as when we say that infants are baptized for the remission of sins, instead of saying for the remission of sin, this is the converse figure of speech, by which the plural number is put in place of the singular; as in the Gospel it is said of the death of Herod, for they are dead which sought the young child’s life, instead of saying, he is dead. And in Exodus: They have made them, Moses says, gods of gold, though they had made only one calf, of which they said: These be your gods, O Israel, which brought you up out of the land of Egypt, — here, too, putting the plural in place of the singular.

Chapter 45. In Adam’s First Sin, Many Kinds of Sin Were Involved.

However, even in that one sin, which by one man entered into the world, and so passed upon all men, and on account of which infants are baptized, a number of distinct sins may be observed, if it be analyzed as it were into its separate elements.

For there is in it pride, because man chose to be under his own dominion, rather than under the dominion of God; and blasphemy, because he did not believe God; and murder, for he brought death upon himself; and spiritual fornication, for the purity of the human soul was corrupted by the seducing blandishments of the serpent; and theft, for man turned to his own use the food he had been forbidden to touch; and avarice, for he had a craving for more than should have been sufficient for him; and whatever other sin can be discovered on careful reflection to be involved in this one admitted sin.