29 Or is He the God of the Jews only? Is He not also the God of the Gentiles? Yes, of the Gentiles also, 30 since there is one God who will justify the circumcised by faith and the uncircumcised through faith. 31 Do we then make void the law through faith? Certainly not! On the contrary, we establish the law (Romans 3:29–31, NKJV).
Law cannot save the one who violates it (Gal. 2:21; 3:21). Law identifies the transgression (sin) and applies just punishment (Rom. 3:19-20; 3:23; 6:23; Gal. 3:10-11). By definition, a system of law is not a system of grace. While the Law of Moses was “holy and just and good,” it did not contain a means of “eternal redemption” (Rom. 7:12; Heb. 9:12; 10:1-4). Therefore, it is essential to acknowledge (the) law’s nature, purposes, and limitations. In the context of today’s passage, Paul laid out what law does (identifies sin and holds the sinner guilty) and what it cannot do (justify the guilty, Rom. 3:19-20). Sinners are “justified freely by His grace through the redemption that is in Christ Jesus” (Rom. 3:23-24). Christ’s death appeases divine wrath “through faith,” saving Jews and Gentiles who have faith in Jesus by grace (Rom. 3:25-26; Eph. 2:8-9). The gospel is God’s power to save Jews and Gentiles (Rom. 1:16-17). Therefore, (1) God justifies Jews by faith (v. 30). Faith is the means of justification for Jews, not the Law of Moses (Acts 15:11; Rom. 10:3-4), and (2) God justifies Gentiles through faith (v. 30). The salvation of Gentiles is completed or finished through faith without adding anything to it (Acts 15:9-10). The “law of faith” does not discount obedient faith but rewards it with salvation (Rom. 3:27; 6:17-18). So, we uphold (establish) God’s law as we understand its nature, purposes, and limitations (Rom. 3:31).