Romans 5:21

that as sin hath reigned unto death, even so might grace reign through righteousness unto eternal life by Jesus Christ, our Lord.

Paul now takes up the thread of the argument which he introduced in v. 12. He introduces the inference from the whole discussion with "wherefore. " As by the trespass of one the result for all men was condemnation, so through the righteousness of One the result for all men is justification of life. When Adam ate of the forbidden fruit, it was a single act of disobedience; but as the consequence of that one trespass the sentence of condemnation has been passed upon all men. On the other hand, the righteousness of Christ, His fulfilling all the demands of the righteousness of the Law, has resulted in the fact that all men are declared to be righteous, the judgment of life being pronounced upon them. And in close connection herewith are two other facts: For just as through the disobedience of the one man many, all men, were presented before God as sinners, so also through the obedience of One all men are presented as just and righteous. First the disobedience of Adam was imputed to all men: God looked upon them as disobedient on account of the sin of Adam; but then came Christ with His perfect obedience for all men, with His complete fulfillment of the Law, and through this vicarious obedience the many, all men, are placed in the rank, in the category of just and righteous people. In this way Christ earned righteousness for all men; the objective justification concerns the whole world: every person without exception belongs to the number of those for whom the benefit of Christ's work has been obtained. Of the fact that this objective justification actually becomes the property of the individual person by faith, Paul speaks elsewhere: but here we have the full comfort of the assurance that the righteousness of Christ was sufficient to place all men in the class of those for whom the obstacles of their salvation have been removed and full righteousness obtained. Thus the comparison between Adam and Christ is closed. But the apostle had above, v. 13, referred to the Law and to Moses. The question might therefore arise what connection these have with the present discussion, since they stand midway between Adam and Christ in history St. Paul states: The Law entered in addition, as an accessory or subordinate thing; it did not have the decisive significance and influence which sin had in its coming. It came only for the purpose that the trespass of Adam might be increased or augmented by actual transgressions of a fixed, written Law. For now that there was a definite norm of the will of God, the number of sins which could be shown as existing was increased enormously. But by that very fact the gracious intention of God toward men received an opportunity to reveal itself. Where, however, sin abounded, grace superabounded; it was dispensed in richest measure and in the very same sphere. And thus the Law did not frustrate, but furthered the gracious end contemplated in the work of Christ. For the dominion of sin, which was emphasized by the Law, had to yield to the dominion of grace: in order that, just as sin reigned in death, so also grace might reign through righteousness unto eternal life through Jesus Christ, our Lord. Death, spiritual as well as temporal, was the sphere or province in which the power or triumph of sin was exercised and manifested. But the goal, the end, of grace is eternal life. The unmerited love of God in Christ Jesus is abundantly and effectively shown in securing eternal life. This glorious effect is secured by means of righteousness, the full and complete righteousness which is through Jesus Christ, our Lord. And so the blessed results of the redemption of Jesus Christ, which are imparted to men by faith, find their glorious realization in that life of everlasting bliss which is the end of justification.

Summary

The apostle describes the blessed consequences of justification as they are guaranteed to us by the love of God and the death of Christ; he shows that, as the sin of Adam has resulted in the condemnation of all men, so the righteousness of Christ resulted in the justification of all men, whose end, for the believers, is eternal life.