Romans 4:15

Law worketh wrath. Legalists who depend on obedience to law for justification from sin are basing their expectations on a false assumption. The function of the law is to reveal sin (ch. 3:20) and to show it to be transgression of God’s will. Far from justifying the sinner, or bringing him peace, it condemns him and brings the wrath of God upon him. Since Paul has already proved that all men have sinned (chs. 1; 2; 3), it follows that any who attempt to be justified by the law will be involved only in wrath and condemnation. Thus the law may produce an effect the very opposite of that which is intended by the promise.

By this verse Paul is by no means denying the necessity of law. He is only clarifying the function of law in the plan of salvation (see on Rom. 3:20, 31; see Gal. 3:21).

No transgression. That is, no disobedience to a known commandment. Paul seems to be using this negative statement to confirm the truth of his positive assertion that where a law does exist, transgression is revealed, and wrath impends. He is trying to make clear to the legalists that if righteousness is not by faith but by law, there is no hope of salvation. For the Jews have a law, and they have all transgressed its requirements. Consequently, they are now exposed to the penalties of transgression, and if the promise of justification without works of law does not extend to them, they are utterly without hope.