Christ who was without sin is said to be made sin for us [2 Cor 5:21], because for our sins he died. Christ who knew no sin, the Father made sin for us: that, as a victim offered for sin was in the law called ‘sin,’ according as it is written in Leviticus, ‘And he shall lay his hand upon the head of his sin’ [e.g. Lev 4:29]; so likewise Christ, being offered for our sins, received the name of sin. ‘That we might be made the righteousness of God in him’: not our righteousness, nor in ourselves.
From Jerome (c.347-420), in Expositio in Primam Epistolam ad Corinthiios (PL 30:820)