Moreover the law entered, that the offence might abound. But where sin abounded, grace did much more abound.
Grace is God’s goodness, the kindness of God’s heart, the good will, the cordial benevolence. It is what God is like. God is like that all the time. You’ll never run into a stratum in God that is hard. You’ll always find God gracious, at all times and toward all peoples forever. You’ll never run into any meanness in God, never any resentment or rancor or ill will, for there is none there. God has no ill will toward any being. God is a God of utter kindness and cordiality and good will and benevolence. And yet all of these work in perfect harmony with God’s justice and God’s judgment. I believe in hell and I believe in judgment. But I also believe that there are those whom God must reject because of their impenitence, yet there will be grace. God will still feel gracious toward all of His universe. He is God and He can’t do anything else….
What God is, God is! When Scripture says grace does “much more abound,” it means not that grace does much more abound than anything else in God but much more than anything in us. No matter how much sin a man has done, literally and truly grace abounds unto that man. AOG103-105
Lord, I am so horribly rebellious and sinful in the light of Your perfect holiness. Thank You that where sin abounds, Your grace abounds even more! Amen. 
As Paul explains more fully in chapter 7, the energizing force behind man’s sin is the Law, which came in that the transgression might increase. Knowing that he would be charged with being antinomian and with speaking evil of something God Himself had divinely revealed through Moses, Paul states unequivocally that “the Law is holy, and the commandment is holy and righteous and good” (Rom. 7:12). Nevertheless, God’s own Law had the effect of causing man’s transgression to increase.
It should be noted here that God’s law-ceremonial, moral, or spiritual-has never been a means of salvation during any age or dispensation. The divinely-ordained place it had in God’s plan was temporary. As the biblical scholar F. F. Bruce has stated, “The law has no permanent significance in the history of redemption” (The Letter of Paul to the Romans [Grand Rapids: Eerdmans, 1985], p. 121). Paul has already declared that Abraham was justified by God solely on the basis of his faith-completely apart from any good works he accomplished and several years before he was circumcised and many centuries before the law was given (4:1–13).
The Law was a corollary element in God’s plan of redemption, serving a temporary purpose that was never in itself redemptive. Disobedience to the law has never damned a soul to hell, and obedience to the law has never brought a soul to God. Sin and its condemnation were in the world long before the law, and so was the way of escape from sin and condemnation.
God gave the Law through Moses as a pattern for righteousness but not as a means of righteousness. The law has no power to produce righteousness, but for the person who belongs to God and sincerely desires to do His will, it is a guide to righteous living.
The law identifies particular transgressions, so that those acts can more easily be seen as sinful and thereby cause men to see themselves more easily as sinners. For that reason the Law also has power to incite men to unrighteousness, not because the Law is evil but because men are evil.
The person who reads a sign in the park that forbids the picking of flowers and then proceeds to pick one demonstrates his natural, reflexive rebellion against authority. There is nothing wrong with the sign; its message is perfectly legitimate and good. But because it places a restriction on people’s freedom to do as they please, it causes resentment and has the effect of leading some people to do what they otherwise might not even think of doing.
The Law is therefore a corollary both to righteousness and to unrighteousness. For the lawless person it stimulates him to the disobedience and unrighteousness he already is inclined to do. For the person who trusts in God, the law stimulates obedience anti righteousness.
Again focusing on the truth that Christ’s one act of redemption is far greater than Adam’s one act of condemnation, Paul exults, But where sin increased, grace abounded all the more. God’s grace not only surpasses Adam’s one sin but all the sins of mankind.
5:20 What Paul has been saying would come as a jolt to the Jewish objector who felt that everything revolved around the law. Now this objector learns that sin and salvation center not in the law but in two federal heads. That being the case, he might be tempted to ask, “Why then was the law given?” The apostle answers, The law entered that the offense might abound. It did not originate sin, but it revealed sin as an offense against God. It did not save from sin but revealed sin in all its awful character.
But God’s grace proves to be greater than all man’s sin. Where sin abounded, God’s grace at Calvary abounded much more!
20 At the conclusion of the chapter, Adam as a figure fades from view. Yet his influence is still present in the mention of sin and death. Paul now introduces another factor—the Mosaic law—to show its bearing on the great issues of sin and righteousness. There is scarcely a subject treated by Paul in Romans that does not call for some consideration of the law. The closest affinity to the thought in v. 20 is found in 3:20: “through the law we become conscious of sin.” Also, ch. 7 traces the relationship between the law and sin in rather elaborate fashion.
The apostle is not maintaining that the purpose of the giving of the law is exclusively “so that the trespass might increase,” because he makes room for the law as a revelation of the will of God and therefore a positive benefit (7:12). The law also serves to restrain evil in the world (implied in 6:15; stated in 1 Ti 1:9–11). Paul uses the unusual verb pareiserchomai (GK 4209) at the beginning of v. 20 (“added”; NASB, “came in”). It has the idea of “slipping in between” (cf. its use in Gal 2:4), as though to say that the law had a limited and temporary role to perform. Similar language is used in Galatians 3:19 (“added”), where the law is regarded as something temporary, designed to disclose the “trespass” aspect of sin and prepare the way for the coming of Christ by demonstrating the dire need for his saving work. Stuhlmacher, 88, writes, “Just as it did between Abraham and Christ (cf. Gal. 3:19ff.), so too the law also ‘came in between’ Adam and Christ (at Sinai).” The function of the law to increase trespass was not recognized in rabbinic Judaism (cf. H.-J. Schoeps, Paul [Philadelphia: Westminster, 1961], 174). From the Sermon on the Mount, however, it appears that Jesus sought to apply the law in just this way, i.e., to awaken a sense of sin in those who fancied they were keeping the law tolerably well but who had underestimated its searching demands and the sinfulness of their own hearts. The law thus finally leads to an understanding of the necessity of grace: “If it had looked as if the law worked hand in hand with sin, it is now made clear that it works hand in hand with grace” (Nygren, 227).
The bad news of this negative influence of the law is countered by good news announced with the words, “grace increased all the more.” The apostle waxes almost ecstatic as he revels in the superlative excellence of the divine overruling that makes sin ultimately serve a gracious purpose. The statement is akin to Paul’s repeated “how much more” argument (cf. vv. 15, 17). The saving grace of God far exceeds the damning sin of Adam’s offspring.
 Tozer, A. W., & Eggert, R. (2015). Tozer on the almighty god: a 365-day devotional. Chicago, IL: Moody Publishers.
 MacArthur, J. F., Jr. (1991). Romans (pp. 308–309). Chicago: Moody Press.
 MacDonald, W. (1995). Believer’s Bible Commentary: Old and New Testaments. (A. Farstad, Ed.) (pp. 1699–1700). Nashville: Thomas Nelson.
 Harrison, E. F., & Hagner, D. A. (2008). Romans. In T. Longman III &. Garland, David E. (Ed.), The Expositor’s Bible Commentary: Romans–Galatians (Revised Edition) (Vol. 11, pp. 100–101). Grand Rapids, MI: Zondervan.