Paul Opposes Peter

In the book of Galatians, Paul confronts Peter over his refusal to include Gentiles who weren't obeying Jewish kosher laws within the family of God, introducing a damnable plus of faith in Jesus plus obedience to the law. Paul explains theologically that justification is never about our obedience, but rather about faith in Jesus Christ, and that our behavior should be a response to the grace we've received, not a means of earning it.