Circumcision: A Seal of the Covenant
Source: TTT
Genesis 17:11
You are to circumcise the flesh of your foreskin, and this will be a sign of the covenant between Me and you.
Romans 4:11
And he received the sign of circumcision as a seal of the righteousness that he had by faith while he was still uncircumcised. So then, he is the father of all who believe but are not circumcised, in order that righteousness might be credited to them.