Romans 2:25-29

For circumcision indeed profiteth, if thou be a doer of the law: but if thou be a transgressor of the law, thy circumcision is become uncircumcision. If therefore the uncircumcision keep the ordinances of the law, shall not his uncircumcision be reckoned for circumcision? and shall not the uncircumcision which is by nature, if it fulfil the law, judge thee, who with the letter and circumcision art a transgressor of the law? For he is not a Jew who is one outwardly; neither is that circumcision which is outward in the flesh: but he is a Jew who is one inwardly; and circumcision is that of the heart, in the spirit not in the letter; whose praise is not of men, but of God.