Romans 5:15

But--"Yet," "Howbeit." not as the offence--"trespass." so also is the free gift--or "the gracious gift," "the gift of grace." The two cases present points of contrast as well as resemblance. For if, &c.--rather, "For if through the offense of the one the many died (that is, in that one man's first sin), much more did the grace of God, and the free gift by grace, even that of the one man, Jesus Christ, abound unto the many." By "the many" is meant the mass of mankind represented respectively by Adam and Christ, as opposed, not to few, but to "the one" who represented them. By "the free gift" is meant (as in Rom 5:17) the glorious gift of justifying righteousness; this is expressly distinguished from "the grace of God," as the effect from the cause; and both are said to "abound" towards us in Christ--in what sense will appear in Rom 5:16-17. And the "much more," of the one case than the other, does not mean that we get much more of good by Christ than of evil by Adam (for it is not a case of quantity at all); but that we have much more reason to expect, or it is much more agreeable to our ideas of God, that the many should be benefited by the merit of one, than that they should suffer for the sin of one; and if the latter has happened, much more may we assure ourselves of the former [PHILIPPI, HODGE].

— Jamieson-Fausset-Brown Commentary (public domain)