John Chrysostom

Then as the fact that many fall into sin even after baptism presented a difficulty, he consequently hastened to meet it, and says not merely "to them that are in Christ Jesus," but adds, "who walk not after the flesh;" so showing that all afterward comes of our listlessness. For now we have the power of walking not after the flesh, but then it was a difficult task. Then he gives another proof of it by the sequel.

Homily on Romans 13 ↗

Theophylact of Ohrid

He said "I serve" instead of "I served"; for he is recalling what was before. Intending to say that "there is now no condemnation" and so on, and to show the ineffable grace of Christ, he recalls what we were before and that with the mind we recognized the good, but "with the flesh," that is, through the weakness of the flesh, we were subject to the law of sin. But now there is "no condemnation for those who are in Christ Jesus," that is, those who have been deemed worthy of baptism. …

Commentary on Romans ↗

Thomas Aquinas

After showing that we are freed from sin and the law through Christ's grace, the Apostle now shows that through the same grace we are freed from damnation. First he shows that through the grace of Christ we are freed from the damnation of guilt; second, from the damnation of punishment, at "and if Christ be in you" (Rom 8:10). In regard to the first he does two things. …

Commentary on Romans ↗