Romans 5:18

Therefore--now at length resuming the unfinished comparison of Rom 5:12, in order to give formally the concluding member of it, which had been done once and again substantially, in the intermediate verses. as by the offence of one judgment came--or, more simply, "it came." upon all men to condenmation; even so by the righteousness of one the free gift came--rather, "it came." upon all men to justification of life--(So CALVIN, BENGEL, OLSHAUSEN, THOLUCK, HODGE, PHILIPPI). But better, as we judge: "As through one offense it [came] upon all men to condemnation; even so through one righteousness [it came] upon all men to justification of life"--(So BEZA, GROTIUS, FERME, MEYER, DE WETTE, ALFORD, Revised Version). In this case, the apostle, resuming the statement of Rom 5:12, expresses it in a more concentrated and vivid form--suggested no doubt by the expression in Rom 5:16, "through one offense," representing Christ's whole work, considered as the ground of our justification, as "ONE RIGHTEOUSNESS." (Some would render the peculiar word here employed, "one righteous act" [ALFORD, &c.]; understanding by it Christ's death as the one redeeming act which reversed the one undoing act of Adam.

— Jamieson-Fausset-Brown Commentary (public domain)