“We who are Jews by nature, and not sinners of the Gentiles…”
The remainder of the chapter expands the idea of Peter’s inconsistency in reverting to legalism (Gal 2:15-21).
We who are Jews by nature,
Paul includes himself in the word “we.” He uses “we” four times in verses 15-17. Paul and Peter were born Jews. That was their condition by “nature.” The Jews tended to hold themselves above Gentiles in self-righteous arrogance.
“By nature” does not mean that Jews were free from sin. The idea is that they are God’s chosen people, God’s people by covenant.
and not sinners of the Gentiles
The Jews viewed Gentiles as “sinners.” The implication is that their belief as God’s chosen people made them superior to the Gentiles as if they somehow gained God’s approbation by something other than the blood of Christ. The Jews received the Old Testament by revelation. They were God’s chosen people by the unadulterated grace of God.
Jews inferred from this that they were somehow morally superior to the Gentiles because God gave them the law. By siding with the Jews in Antioch of Syria, Peter inferred that religion and not grace is the principle of salvation and the Christian life. But the law is not the way to salvation even in the Old Testament (Genesis 15:6). Paul will develop this in the next chapter.
Christians stand in Christ’s perfect righteousness before God eternally because they trust the blood of Christ to forgive them.
The gap between God and people is one of infinite degree. When people go to Heaven, they go there on God’s terms, not their own. Only Jesus could bridge the gap between the absolute and perfect righteousness of God and the relative righteousness of humankind. It is what He did on the cross by paying for our sins.
People cannot keep the law by human means (Romans 3:20,28; 6:14; Galatians 2:16, 19-21; 3:2,5,10, 21; Philippians 3:9). It is too perfect and too huge for them to sustain. Jesus fulfilled the law in every respect. We also fulfill the law when we believe in His death on the cross to forgive our sins.
“For the law of the Spirit of life in Christ Jesus has made me free from the law of sin and death. For what the law could not do in that it was weak through the flesh, God did by sending His own Son in the likeness of sinful flesh, on account of sin: He condemned sin in the flesh, that the righteous requirement of the law might be fulfilled in us who do not walk according to the flesh but according to the Spirit” (Romans 8:2-4).
Christ abrogated our responsibility to live up to the law because He fulfilled it for us.
“For Christ is the end of the law for righteousness to everyone who believes” (Romans 10:4).
There is no salvation outside Jesus Christ and His work on the cross.