Since the concept of works righteousness involves a denial of sin, it entails a form of self-deception that seems reasonable to our sin corrupted way of thinking. For that reason, many people find it hard to understand that we are not saved by what we do, but by what Christ did for us on the cross. Therefore, to more effectively get that message across, the Apostle Paul drew an analogy between the sin of one man (Adam), and the death of one man (Christ). That analogy is found in the fifth chapter of His Epistle to the Romans.

AN OVERVIEW

    Paul begins by pointing out the spiritual significance of Adam’s sin. He then draws a parallel between Adam and Christ, while mentioning that the parallel is between two events that have dissimilar effects. The point of his parallel is that just as we were made sinners by what someone else did, we are made righteous and saved by what someone else did.

THE SIGNIFICANCE OF ADAM’S SIN

12  Wherefore, as by one man sin entered into the world, and death by sin; and so death passed upon all men, for that all have sinned:
13  (For until the law sin was in the world: but sin is not imputed when there is no law.)
14 Nevertheless death reigned from Adam to Moses, even over them that had not sinned after the similitude of Adam’s transgression, who is the figure of him that was to come.

[Comment: Paul begins with the fact that we are all sinners, and we are all going to die because of what Adam did (verse 12). He then tells us that the effect of Adam's sin goes far deeper than what is dealt with in the law, the proof being that people were dying (and going to hell) before the law was ever given, and, therefore, before the sins of the law were ever imputed to men (verses 13 and14).]

THE PARALLEL

15  But not as the offence, so also is the free gift. For if through the offence of one many be dead, much more the grace of God, and the gift by grace, which is by one man, Jesus Christ, hath abounded unto many.
16 And not as it was by one that sinned, so is the gift: for the judgment was by one to condemnation, but the free gift is of many offences unto justification.

[Comment: Paul mentions the fact that what Adam did had the opposite effect of what Christ did, nevertheless, there is a similarity in that in both cases what was done by one affected all (verse 15). As the sin of one man (Adam) brought death and condemnation, the gift (of God's grace) obtained for us by one man (Christ) removes sin and condemnation, thus justifying us in the sight of God (verses 15 and 16).]

17  For if by one man’s offence death reigned by one; much more they which receive abundance of grace and of the gift of righteousness shall reign in life by one, Jesus Christ.)
18  Therefore as by the offence of one judgment came upon all men to condemnation; even so by the righteousness of one the free gift came upon all men unto justification of life.
19  For as by one man’s disobedience many were made sinners, so by the obedience of one shall many be made righteous.

[Comment: The parallel that Paul draws, tells us the spiritual significance of both Adam's sin, and Christ's sacrificial death on our behalf. As one man's sin brought death and condemnation upon all, one man's obedience made the gift of life and righteousness available to all.]

20  Moreover the law entered, that the offence might abound. But where sin abounded, grace did much more abound:
21  That as sin hath reigned unto death, even so might grace reign through righteousness unto eternal life by Jesus Christ our Lord.

[Comment: Since he previously made a distinction between the sin that is in our nature through the fall, and transgression of the written law, Paul makes it clear that the grace that is ours in Christ covers all sin. As sin brought death, grace alone exonerates us that we might have eternal life through Jesus Christ our Lord.]

CONCLUSION

    Paul drew this parallel in order to emphasize the fact that we are not made righteous by what we do, but by what Christ did for us. In verse fifteen we are told that grace is a gift, in verse sixteen we are told that justification is a gift, and in verse seventeen we are told that righteousness is a gift. The point being that our salvation is a gift. As it is written, "For the wages of sin is death; but the gift of God is eternal life through Jesus Christ our Lord" (Romans 6:23).