Romans 3
3:1-2. Paul’s argument, that God’s justice is not partial, and that all men by nature have the Law written on their hearts (2:11-15), leads naturally to the rhetorical question asked in v.1.
By analogy to v.2, it is actually a great advantage to drive on a road that is marked with traffic signs, in contrast to no signs and everyone driving according to the natural law of self-preservation. This is true even if everyone is a traffic sign transgressor. The Jew’s had the signs. (See also 9:4-5).
3:3-8. The quote from Ps.51:4 is preceded by David saying, “Against Thee, Thee only, I have sinned, and done what is evil in Thy sight.” Therefore, the condemnation by God’s Law is vindicated, and David’s sin demonstrates God’s righteousness in judgment. Well then, since David’s sin shows how righteous God is and brings him honor, wouldn’t it be wrong of God to inflict wrath upon him? This is how some people reason (5-7). (In fact, that is how hell is reasoned out of existence. A good God wants to demonstrate mercy, and would not inflict wrath.)
3:7-8. The opponents of the gospel of grace accuse Paul of reasoning as above. The more sin, the more grace. Therefore, they slander Paul as teaching the more sin the better.
3:9. The antecedents of “we” and “they” are the Jews and the Greeks of chapter 2 (cf.2:9-10).
3:10-18. The testimony of several Psalms and Isaiah to the depravity of man.
3:19-20. The first use of the Law is the conviction of sin, “for through the Law comes the knowledge of sin.” Therefore, the Law cannot be our justifier.
3:21. “But now…,” i.e., now in the fullness of time (Gal.4:4), these “last days,” when God has accomplished in Christ all he promised in the Law and the Prophets (as signified by Moses and Elijah at the transfiguration, Luke 9:28 ff.).
3:21-30. The Law and the Prophets witness to the gospel, how God can remain righteous, pouring out his wrath justly upon our violations of his holy Law, and yet keep his promises of mercy and redemption. It is by faith in his free grace in Christ Jesus (24). Faith in his blood shed for us shows God to be righteous in passing over the past sins of the OT faithful (the sins previously committed, v.25), and also the sins of the present time (26). There is one salvation for the past and the present, both for the Jew and the Gentile, and it is not of our own works of merit, but of God’s grace. Boasting is excluded (27; Eph.2:8-9).
3:25. The word propitiation, very properly used here, is well defined as follows (by contrasting it to expiation): “Propitiation means the turning away of anger; expiation is rather the making of amends for a wrong. Propitiation is a personal word; one propitiates a person. Expiation is an impersonal word; one expiates a sin or a crime.” Leon Morris, The Atonement, Inter-Varsity Press, 1983, p.151.
Significantly, this same word is used in Heb.9:5 (there translated “the mercy seat,”) as the name for the lid covering the tables of the Law in the Ark of the Covenant, on which the blood of Atonement was sprinkled. (Cf. Heb.2:17; 1 John 2:2, 4:10; also see my notes at Luke 18:9-14).
3:31. “…we establish the Law.” Christ’s propitiating blood demonstrates the righteousness of God (25-26). Blood had to be shed to satisfy the Law, which could not be nullified. Paul’s argument establishes the Law, because in the death of Jesus not a single sin of his people is passed over unpunished by the Law. Thus God is righteous when he declares them righteous. Who then is justified? The one who has faith in Jesus the righteous redeemer whose blood is the propitiation for our sins (24-26).