Galatians 2:16

yet knowing that a man is not justified by the works of the law but through faith in Jesus Christ, even we believed on Christ Jesus, that we might be justified by faith in Christ, and not by the works of the law: because by the works of the law shall no flesh be justified. [If thou, being a Jew to begin with, livest, as is shown by your past custom, like a Gentile, and not like the Jews, by what right do you demand, by your changed custom, that the Gentiles should live like Jews? For even you and I, both being born Jews, and both taking the best view of ourselves possible, and regarding ourselves after the most untempered and unwarranted pride and prejudice of our race as infinitely superior to the degraded heathen (as we were wont to call them), both in righteousness and acceptability to God, even we, I say, despite all this, were forced to see and acknowledge that a man is not justified by those works of the law in which we trusted, but through faith in Jesus Christ, so that we believed on Christ Jesus that we might obtain the justification that comes through him, rather than the vain and insufficient justification of the law, for the Scripture itself (Psalms 143:2) says," By the works of the law shall no flesh be justified."]