12 Therefore, just as sin came into the world through one man [Adam], and death through sin, and so death [both physical and spiritual] spread to all men because all sinned—
because all sinned [aorist indicative—Adam’s actual sin at one point in the past]—
The “sinned” in this phrase cannot carry the idea of personal sin because of the use of the word “one” in this section of Romans. We died because of the trespass of “one” (v.15), the judgment followed “one” sin (v.16), by the trespass of “one man” sin reigned (v.17), “one” trespass was condemnation for all men (v.18), and “through the disobedience of the one man the many were made sinners” (v.19).
Following the example of Adam is not the issue. Somehow, humanity is caught up in the original sin of Adam. The emphasis of this passage is on what the two men did. Christ provided salvation without merit on our part, therefore, death in Adam is not punishment for personal sin; it is what happened in Adam that is important here. The issue is what Christ and Adam did to their descendants.
This phrase cannot mean “because all men sinned personally.” If the latter were true then the word “sinned” would have to be in the present tense, but it is not. The Greek indicates that the sin occurred in a single past action when Adam sinned. All men sinned through the one man Adam (vv. 15,17).
Adam acted on behalf all persons as our federal head.
Immediate imputation of sin to man means that men stood their probation in Adam, their representative head. Adam’s act was deemed their act; his sin was their sin. They sinned in Adam (5:12, 18-19; 1 Co 15:22). Adam is thus the representative head of his posterity. God’s threats to him were threats for all men. The first Adam’s sin is a representative act just as the act of the Last Adam is a representative act. Jesus’ act is the judicial ground for salvation.
All imputation, whether of Adam’s sin or Christ’s righteousness, rests on the principle of union. Adam and his posterity are one in union. He is not one with angels. Fallen angels committed individual transgressions of their own. Thus, it is just to impute Christ’s righteousness to a believer but not to an unbeliever because the believer has been united to Christ by faith. The unbeliever is not in the same union.
Men must sin in Adam to be justly punished for Adam’s sin. That participation in his sin requires union with Adam. The human race acted in the sin of Adam and sinned in his sin.
The imputation of Adam’s sin rests upon a different kind of union than union with Christ. Union with Adam rests upon natural union. This is a union of constitution. However, there is no race-unity in justification. All were in Adam when he sinned; yet, all men were not in Christ when He obeyed. All were propagated by Adam and inherited his sin; no man was propagated by Christ and no one inherits His righteousness.
Sin begins with Adam and flows to his posterity (race); redemption starts with the individual. All men sin; some are justified. Union in Adam is physical and union in Christ is spiritual. Union in Adam is natural representation but union in Christ is spiritual representative. Union in Adam is by generation but union in Christ is by regeneration. In Adam man is in a species but in Christ the believer is an individual. Every human being is in Adam but only a few are in Christ (elect).
Ga 1:15 But when it pleased God, who separated me from my mother’s womb and called me through His grace,