TSK · Genesis 17:12

Abraham circumcised his son, Isaac, when he was eight days old, as God had commanded him.

When a stranger shall live as a foreigner with you, and will keep the Passover to Yahweh, let all his males be circumcised, and then let him come near and keep it; and he shall be as one who is born in the land: but no uncircumcised person shall eat of it.

It happened on the eighth day, that they came to circumcise the child; and they would have called him Zacharias, after the name of the father.

Moses has given you circumcision (not that it is of Moses, but of the fathers), and on the Sabbath you circumcise a boy.

For he is not a Jew who is one outwardly, neither is that circumcision which is outward in the flesh;