What shall we say, then? That Gentiles who did not pursue righteousness have attained it, that is, a righteousness that is by faith; but that Israel who pursued a law that would lead to righteousness did not succeed in reaching that law. Why? Because they did not pursue it by faith, but as if it were based on works. They have stumbled over the stumbling stone.
Romans 9:30-32 (ESV)
In his letter to the Romans, the Apostle Paul states that while the Jews tried to work for their salvation but did not obtain it, the Gentiles did not work for their salvation but received it through faith.
The salvation of the Gentiles is part of God’s incredible plan to save all who are undeserving and unworthy. This generous act of God’s grace in Christ was “a stumbling stone” for many during Paul’s time since they preferred to place their confidence in their own self-justification through works.
Legalism is still a real and present threat to the purity of the gospel.
We are to live by faith, but living by faith does not imply we disregard the purpose of the law. The primary reason for the law was to point us to Christ. Paul says in Romans 3:31 that we uphold the law by our faith in Christ, not by trying to keep it. By satisfying all the righteousness requirements of the law on our behalf, Christ has already perfected the purpose for which the law was given (Romans 10:4).
We are given Christ’s perfect righteousness as we are united in Him. Thus, sanctification is living out the truth of our justification. We desire and will want to do all things right by God, not because of the law, but because of faith (Romans 4:14). Practically, we are pursuing a lifestyle of following Jesus and walking in obedience to Him. As His Spirit inscribes His living word in us (cf. James 1:21; Hebrews 8:10), we grow more and more like Him by His will.