Commentaries:
Robertson's Word Pictures (NT)
Came in beside (pareishlqen). Second aorist active indicative of double compound pareiserxomai, late verb, in N.T. only here and Galatians 2:4 which see. See also eishlqen in verse Romans 5:12. The Mosaic law came into this state of things, in between Adam and Christ.
That the trespass might abound (ina pleonash to paraptwma). It is usual to explain ina here as final, as God's ultimate purpose. So Denney who refers to Galatians 3:19 ff.; Romans 7:7 f. But Chrysostom explains ina here as ekbasiv (result). This is a proper use of ina in the Koin‚ as we have seen. If we take it so here, the meaning is "so that the trespass abounded" (aorist active subjunctive of pleonasw, late verb, see on II Thessalonians 1:3; II Corinthians 8:15). This was the actual effect of the Mosaic law for the Jews, the necessary result of all prohibitions.
Did abound more exceedingly (upereperisseusen). First aorist active indicative of uperperisseuw. Late verb, in N.T. only here and II Corinthians 7:4 which see. A strong word. If pleonazw is comparative (pleon) perisseuw is superlative (Lightfoot) and then uperperisseuw goes the superlative one better. See uperpleonazw in I Timothy 1:14. The flood of grace surpassed the flood of sin, great as that was (and is).
Other Robertson's Word Pictures (NT) entries containing Romans 5:20:
John 10:10
Romans 11:11
1 Corinthians 15:56
Galatians 2:4
1 Thessalonians 4:11
1 Timothy 1:14
James 4:6
2 Peter 3:16
DISCLAIMER: Church of the Great God (CGG) provides these resources to aid the individual in studying the Bible. However, it is up to the individual to "prove all things, and hold fast to that which is good" (I Thessalonians 5:21). The content of these resources does not necessarily reflect the views of CGG. They are provided for information purposes only.