Romans 5:20

One of the purposes of the Mosaic Law was to illuminate the sinfulness of people. It did so at least by exposing behavior that was until then not obviously contrary to God’s will. God did this to prove man’s sinfulness to him.

"The fact and power of ’sin’ introduced into the world by Adam has not been decreased by the law, but given a new dimension as rebellion against the revealed, detailed will of God; sin has become ’transgression’ . . ." [Note: Moo, p. 348. Cf. 7:13; Galatians 3:19.]

Paul’s statement "the Law came in that" can be understood as both a purpose clause and a result clause. [Note: Witmer, p. 460.] However when God provided Jesus Christ, He provided grace (favor) that far exceeded the sin that He exposed when He provided the Law. We could translate "abounded" or "increased" (Romans 5:20) "super-abounded."

"The apostle waxes almost ecstatic as he revels in the superlative excellence of the divine overruling that makes sin serve a gracious purpose." [Note: Harrison, p. 65.]

The contrast in this verse deals with the significances of Adam’s act and Christ’s act. The Law showed the significance of Adam’s sin more clearly, and God’s provision of Christ showed the significance of God’s grace more clearly.