The therefore of Romans 5:12 covers Romans 1:16 to Romans 5:11: the working of sin and grace are traced up to their fountain-heads in Adam and Christ (cf. 1 Corinthians 15:45-47). Adam (Heb. man) stands for humanity racially. Two opposing currents run through man's life, each with its personal source (Romans 5:12-14; Romans 5:18 f.); but with this broad correspondence, there are signal contrasts (Romans 5:15-17); grace is the ultimate victor (Romans 5:20 f.).
Romans 5:12 affirms the solidarity of mankind in sin and death. The clause for that all sinned repeats the cardinal declaration of Romans 3:23, and needs no complementary in him (Adam): wherever death enters, sin has opened the door.
Romans 5:13 f. deals with the seeming exception of pre-Mosaic times: all sinned, I say (Romans 5:12); for there was sin in the world up to the time of law Moses-' law did not create sin, but matured it (cf. Romans 5:20; Romans 7:7 ff., Romans 7:13). Yet, some one says, sin is not taken into account where no law exists (see Romans 4:15).For all that, replies Paul, death reigned from Adam to Moses, even over those who did not, like Adam, transgress an explicit command. The inference goes without saying: the intervening generations violated some law; the sequence of sin and death is itself matter of primordial law (Romans 8:2). Death was universal from Adam downwards; sin was universal; ipso facto, law was universal. This Paul had shown in Romans 2:14-16, in another way. Through all ages, amongst all races, sin genders death (James 1:15); at the bottom there is no difference (Romans 3:22). The complement of just as (Romans 5:12) is virtually contained in the last clause of Romans 5:14, who (Adam) is a type of the One to come. What Adam was to his kind in point of transgression, this Other is to be in the contrary sense.
Romans 5:15 f. But Christ's grace in its potency is far more than a counterpoise to the race-sin. Paul pits the grace of God and. the grace of the One Man conjointly against the trespass. Romans 5:15 marks the contrast in kind, Romans 5:16 in degree: the sin of one man resulted in general condemnation, while the justification-bringing act of grace. dealt with many trespasses.
Romans 5:17. Finally, Christ's grace triumphantly reverses the effects of Adam's fall, turning the slaves of death into lords of life. To speak of righteousness as a gift received is another way of affirming Justification by Faith (cf. Romans 3:24, Romans 4:4 f.).
Romans 5:18 f., Romans 5:21. Thus the two headships are vastly disparate: on the one side, trespass, disobedience, sin, bearing fruit in condemnation, sinfulness (were constituted sinners, Romans 5:19), death; on the other, rectification (the one justificatory act or sentence, Romans 5:18), obedience, grace, resulting in justification, righteousness, life eternal (terms of status, character, destiny).The many versus the one of Romans 5:19 = all versus one of Romans 5:18. In Romans 5:14; Romans 5:17, death came to reign through sin: in Romans 5:21, sin reigns in death; for mortality brings home to men sin's domination, as life eternal will display the regnancy of grace.
Romans 5:20 brings in the law by the way, as multiplying the (Adam's) trespass so as to further, however, the superabounding of grace (cf. Romans 4:15, Romans 7:7-13, and Galatians 3:19 f.). This paragraph extends the scope of Christ's redemption from the primeval fall on to the glories of eternal destiny.