Genesis 17:27

And all the men of his house, born in the house, and bought with money of the stranger, were circumcised with him.

Cross-reference

Genesis 17:23 describes Abraham circumcising his entire household that same day — this verse confirms the action is complete.

Genesis 14:14 introduces Abraham's 318 trained servants 'born in his house' — the same group circumcised here as part of the covenant.

Genesis 18:19 reveals God's purpose for Abraham — that he command his household in righteousness. Genesis 17:27 shows him doing exactly that by circumcising all his household.