John Wesley on 2 Corinthians 5:21

He made him a sin offering, who knew no sin - A commendation peculiar to Christ. For us - Who knew no righteousness, who were inwardly and outwardly nothing but sin; who must have been consumed by the divine justice, had not this atonement been made for our sins. That we might be made the righteousness of God through him - Might through him be invested wi th that righteousness, first imputed to us, then implanted in us, which is in every sense the righteousness of God.