Deuteronomy 10:16
16 Circumcise therefore qthe foreskin of your heart, and be no longer rstubborn.
Jeremiah 9:26
26 cEgypt, Judah, Edom, the sons of Ammon, Moab, and dall who dwell in the desert who cut the corners of their hair, for all these nations are uncircumcised, and all the house of Israel are euncircumcised in heart.”
Romans 2:28–29
28 For sno one is a Jew twho is merely one outwardly, nor is circumcision outward and physical. 29 But a Jew is one uinwardly, and vcircumcision is a matter of the heart, by the Spirit, not by the letter. wHis praise is not from man but from God.