The Apostle Paul
Romans 5:15BSB·traditional attribution

But the gift is not like the trespass. For if the many died by the trespass of the one man, how much more did God’s grace and the gift that came by the grace of the one man, Jesus Christ, abound to the many!

John Calvin Reformed @genevareformer

15. But not as the offense, etc. Now follows the rectifying or the completion of the comparison already introduced. The Apostle does not, however, very minutely state the points of difference between Christ and Adam, but he obviates errors into which we might otherwise easily fall, and what is needful for an explanation we shall add.

Matthew Henry Presbyterian @wholebiblehenry

The apostle here describes the fountain and foundation of justification, laid in the death of the Lord Jesus. The streams are very sweet, but, if you run them up to the spring-head, you will find it to be Christ's dying for us; it is in the precious stream of Christ's blood that all these privileges come flowing to us: and therefore he enlarges upon this...

Commenting on Romans 5:6-21

John Gill Reformed Baptist @doctorgill

But not as the offence, so also is the free gift,.... By "the offence", or "fall", as the word signifies, is meant the first sin of Adam; by which he offended God, and fell from that estate in which he was created, and all his posterity with him; and by the "free gift" is meant, the righteousness of Christ, which justifies from that, and all...