A.T. Robertson Commentary Romans 5:16

"And not as through one that sinned, [so] is the gift: for the judgment [came] of one unto condemnation, but the free gift [came] of many trespasses unto justification." — Romans 5:16 (ASV)

Through one that sinned (δι' ενος αμαρτησαντος). "Through one having sinned." That is Adam. Another contrast, difference in source (εκ).

Of one (εξ ενος). Supply παραπτωματος, Adam's one transgression.

Of many trespasses (εκ πολλων παραπτωματων). The gift by Christ grew out of manifold sins by Adam's progeny.

Justification (δικαιωμα). Act of righteousness, result, ordinance (1:32; 2:26; 8:4), righteous deed (5:18), verdict as here (acquittal).