Romans 1:16 (BSB)

I am not ashamed of the gospel, because it is the power of God for salvation to everyone who believes, first to the Jew, then to the Greek.

From Romans 1. Also in the ESV.

Commentary on Romans 1:16

• John Calvin (Reformed), Calvin's Commentaries on Romans 1:16: 16. I am not indeed ashamed, etc. This is an anticipation of an objection; for he declares beforehand, that he cared not for the taunts of the ungodly; and he thus provides a way for himself, by which he proceeds to pronounce an eulogy on the value of the gospel, that it might not appear contemptible to the Romans.
• Matthew Henry (Presbyterian), Matthew Henry's Complete Commentary on Romans 1:16-18: Paul here enters upon a large discourse of justification, in the latter part of this chapter laying down his thesis, and, in order to the proof of it, describing the deplorable condition of the Gentile world. His transition is very handsome, and like an orator: he was ready to preach the gospel at Rome, though a place where the gospel was run down by those...
• John Gill (Reformed Baptist), Exposition of the Old and New Testaments on Romans 1:16: For I am not ashamed of the Gospel of Christ,.... The reason why he was so ready and willing to preach it, even where he ran the greatest risk of his character and life, was, because it was "the Gospel of Christ" he preached, and he was not ashamed of it.
• Albert Barnes (Presbyterian), Barnes' New Testament Notes on Romans 1:16: Verse 16. For I am not ashamed, etc. The Jews had cast him off, and regarded him as an apostate; and by the wise among the Gentiles he had been persecuted, and despised, and driven from place to place, and regarded as the filth of the world, and the offscouring of all things, () but still he was not ashamed of the gospel.