Having called the law good, Paul faces the next puzzle. He had said the commandment brought death to him (Romans 7:10-11). So did a good thing turn into death? The question tests where the blame really belongs. Barnes says Paul repeats that "the fault was not in the law, but was in himself, and in his sinful propensities." Gill agrees: "not the law, but sin, was the cause of death."

Paul answers, "God forbid," and then explains: "But sin, that it might appear sin, working death in me by that which is good; that sin by the commandment might become exceeding sinful" (Romans 7:13). Sin, not the law, produced death, and the commandment exposed sin's true character. He goes on: "we know that the law is spiritual: but I am carnal, sold under sin" (Romans 7:14).

"God forbid" is again the Greek me genoito, "may it never be." The question's verb "made" (egeneto, "became") and the genoito of the answer are forms of the same verb, so the reply turns the question's own word back on it: did the good become death? May it never become so.

"Exceeding sinful" translates kath' hyperbolen, literally "according to excess," which the ESV renders "sinful beyond measure." Matthew Henry explains that by the commandment sin "becomes exceedingly sinful; that is, it appears to be so."

God's good law becomes the light in which sin is seen for what it is. Matthew Henry's picture fits: when the commandment came, "sin revived, as the dust in a room rises (that is, appears) when the sun-shine is let into it." The sunlight does not create the dust. It shows it.

Romans 7 shows how sin twists even good things, "taking occasion by the commandment" (Romans 7:11). Paul's honesty here sets up his cry for a deliverer (Romans 7:24) and God's answer in Christ (Romans 7:25; Romans 8:1-3).