The Great Exchange
So "God laid on Christ the iniquities of us all," that "by his stripes we might be healed," Isa. liii. 5, 6. Our iniquity was laid on him, and he bare it, verse 11; and through his bearing of it we are freed from it. His stripes are our healing. Our sin was his, imputed unto him; his merit is ours, imputed unto us. “He was made sin for us, who knew no sin; that we might become the righteousness of God in him,” 2 Cor. v. 21. This is that commutation I mentioned: he was made sin for us; we are made the righteousness of God in him. God not imputing sin unto us, verse 19, but imputing righteousness unto us, does it on this ground alone that “he was made sin for us.” And if by his being made sin, only his being made a sacrifice for sin is intended, it is to the same purpose; for the formal reason of any thing being made an expiatory sacrifice, was the imputation of sin unto it by divine institution. The same is expressed by the same apostle, Rom. viii. 3, 4, “God sending his own Son in the likeness of sinful flesh, and for sin, condemned sin in the flesh; that the righteousness of the law might be fulfilled in us.” The sin was made his, he answered for it; and the righteousness which God requires by the law is made ours: the righteousness of the law is fulfilled in us, not by our doing it, but by his. This is that blessed change and commutation wherein alone the soul of a convinced sinner can find rest and peace. So he “has redeemed us from the curse of the law, being made a curse for us, that the blessing of Abraham might come on us,” Gal. iii. 13, 14. The curse of the law contained all that was due to sin. This belonged unto us; but it was transferred on him. He was made a curse; whereof his hanging on a tree was the sign and token. Hence he is said to “bear our sins in his own body on the tree,” 1 Pet. ii. 24; because his hanging on the tree was the token of his bearing the curse: “For he that is hanged is the curse of God,” Deut. xxi. 23. And in the blessing of faithful Abraham all righteousness and acceptation with God is included; for Abraham believed God, and it was imputed unto him for righteousness.
(Works Of John Owen, vol. 5: Faith And Its Evidences, 35)