Here is St. John Chrysostom’s homily on that verse:
newadvent.org/fathers/220211.htm
Here is what the Ignatius Study Bible says:
5:21 made him to be sin: Jesus was not made a sinner or personally counted guilty of sin on the Cross. Rather, he bore the curse of death that mankind incurred because of sin (Gal 3:13; 1 Pet 2:22–24), even though he himself
knew no sin, i.e., committed no sin (Jn 8:46; 1 Jn 3:5) (CCC 602–3). ● Paul adopts the idiom of the Greek OT, where “sin” is a shorthand expression for a Levitical “sin offering” (Lev 4:21; 5:12; 6:25). Isaiah uses this same language for the suffering Messiah, who was expected to make himself an “offering for sin” (Is 53:10).
the righteousness of God: An important expression in Paul’s writings. It can refer
(1) to God’s own righteousness that is manifest to the world when he is faithful to his covenants (Rom 3:25–26) and
(2) to the gift of righteousness that God imparts to the baptized (Phil 3:9). See note on Rom 1:17.
—The Ignatius Catholic Study Bible: The New Testament (San Francisco: Ignatius Press, 2010), 320.
Here is what the Navarre Bible Commentary says:
5:21. “He made him to be sin”: obviously St Paul does not mean that Christ was guilty of sin; he does not say “to be a sinner” but “to be sin”. “Christ had no sin,” St Augustine says; “he bore sins, but he did not commit them” (
Enarrationes in Psalmos, 68, 1, 10).
According to the rite of atoning sacrifices (cf. Lev 4:24; 5:9; Num 19:9; Mic 6:7; Ps 40:7) the word “sin”, corresponding to the Hebrew
ašam, refers to the actual act of sacrifice or to the victim being offered. Therefore, this phrase means “he made him a victim for sin” or “a sacrifice for sin”. It should be remembered that in the Old Testament nothing unclean or blemished could be offered to God; the offering of an unblemished animal obtained God’s pardon for the transgression which one wanted to expiate. Since Jesus was the most perfect of victims offered for us, he made full atonement for all sins. In the Letter to the Hebrews, when comparing Christ’s sacrifice with that of the priests of the Old Testament, it is expressly stated that “every priest stands daily at his service, offering repeatedly the same sacrifices, which can never take away sins. But when Christ had offered for all time a single sacrifice for sins, he sat down at the right hand of God, then to wait until his enemies should be made a stool for his feet. For by a single offering he has perfected for all time those who are sanctified” (Heb 10:11–14).
This concentrated sentence also echoes the Isaiah prophecy about the sacrifice of the Servant of Yahweh; Christ, the head of the human race, makes men sharers in the grace and glory he achieved through his sufferings: “upon him was the chastisement that made us whole, and with his stripes we are healed” (Is 53:5).
Jesus Christ, burdened with our sins and offering himself on the cross as a sacrifice for them, brought about the Redemption: the Redemption is the supreme example both of God’s justice—which requires atonement befitting the offence—and of his mercy, that mercy which makes him love the world so much that “he gave his only Son” (Jn 3:16). “In the Passion and Death of Christ—in the fact that the Father did not spare his own Son, but ‘for our sake made him sin’—absolute justice is expressed, for Christ undergoes the Passion and Cross because of the sins of humanity. This constitutes even a ‘superabundance’ of justice, for the sins of man are ‘compensated for’ by the sacrifice of the Man-God. Nevertheless, this justice, which is properly justice ‘to God’s measure’, springs completely from love, from the love of the Father and of the Son, and completely bears fruit in love. Precisely for this reason the divine justice revealed in the Cross of Christ is ‘to God’s measure’, because it springs from love and is accomplished in love, producing fruits of salvation. The divine dimension of redemption is put into effect not only by bringing justice to bear upon sin, but also by restoring to love that creative power in man thanks to which he once more has access to the fullness of life and holiness that come from God. In this way, redemption involves the revelation of mercy in its fullness” (John Paul II,
Dives in misericordia, 7).
—Saint Paul’s Letters to the Corinthians, The Navarre Bible (Dublin; New York: Four Courts Press; Scepter Publishers, 2005), 155–156.
