Paul had just finished a section of rebuke regarding hypocritical Jews. The tone almost seems to imply that being Jewish had absolutely no advantages. Is that true, that being Jewish has no advantages? Paul answered in this next section.
Romans 3:1-4 (KJV)
What advantage then hath the Jew? or what profit is there of circumcision?
Much every way: chiefly, because that unto them were committed the oracles of God.
For what if some did not believe? shall their unbelief make the faith of God without effect?
God forbid: yea, let God be true, but every man a liar; as it is written, That thou mightest be justified in thy sayings, and mightest overcome when thou art judged.
Paul asked the question himself in verse 1. Is there any advantage in being Jewish, or is there any profit in circumcision? Considering all of the antisemitism in the world today, it would seem that being Jewish is about the last nationality anyone would want to be. And circumcision, as a sign of covenantal relationship to God, has been pooh-poohed even by those who believe themselves to be in a relationship to the God of Abraham, Isaac, and Jacob.
Paul answered his own question in verse 2. There is advantage to being Jewish and circumcised. Paul claimed that there were many advantages. The most important is that the oracles or Word of God have been committed to the Jews. Throughout the Jews' history the Word of God has been held sacred by them, protected and preserved. This small group of people have committed their lives to that Word. And through that Word, or Torah, they knew about forgiveness and faith. The Gentiles, on the other hand, only knew enough through the Creation and the conscience to be held accountable for their sin.
Yet, if some of the Jews have not believed the Word of God, does that make God's means of salvation any less effective (verse 3)? In other words, do the actions of the Jews, or their unbelief make God a liar because He "failed" with His chosen people? Can He not save? Is the Torah ineffective in its intended purpose? Paul forcefully responded in verse 4, "God forbid!" Even if every man were a liar, God would be true! Then Paul quoted part of Psalm 51:4.
Psalm 51:4 (KJV)
Against thee, thee only, have I sinned, and done this evil in thy sight: that thou mightest be justified when thou speakest, and be clear when thou judgest.
By this quote, Paul was alluding to the entire Psalm that speaks of individual sin and the righteousness of God's judgment. David, the author of the Psalm, in recognizing his sin, declared God innocent of any wrongdoing in David's punishment.
Psalm 51:10-12 (KJV)
Create in me a clean heart, O God; and renew a right spirit within me.
Cast me not away from thy presence; and take not thy holy spirit from me.
Restore unto me the joy of thy salvation; and uphold me with thy free spirit.
God had not failed in David's case, and He had not failed with the Jews. Although there are corporate aspects to salvation, God saves us one by one, by grace through faith. God is not at fault for the Jews' lack of belief. God's gift of Torah to the Jews still stands as the vehicle of understanding God's means of salvation.