What does the Bible say about Peter's error in Galatians 2?

In Galatians 2, Peter's critical error was his public withdrawal from eating with Gentile believers due to fear of criticism from Jewish brethren. This action contradicted the essence of the gospel, which emphasizes salvation by grace through faith in Christ alone. Paul confronted Peter before all, highlighting that his behavior implied the Gentiles were less acceptable to God, undermining Christ's sufficiency for salvation. By this action, Peter re-established a divide based on law adherence, which Paul vehemently opposed as false doctrine.