On that very day Abraham took his son Ishmael and all those born in his household or purchased with his money—every male among the members of Abraham’s household—and he circumcised them, just as God had told him.
23. And Abraham took Ishmael Moses now commends the obedience of Abraham because he circumcised the whole of his family as he had been commanded. For he must, of necessity, have been entirely devoted to God, since he did not hesitate to inflict upon himself a wound attended with acute pain, and not without danger of life.
We have here Abraham's obedience to the law of circumcision. He himself and all his family were circumcised, so receiving the token of the covenant and distinguishing themselves from other families, that had no part nor lot in the matter. 1. It was an implicit obedience: He did as God had said to him, and did not ask why or wherefore.
Commenting on Genesis 17:23-27
And Abraham took Ishmael his son,.... To circumcise him; he took his son first, to set an example to his servants, and that they might the more readily comply when they saw that Abraham's son, and at that time his only son, was circumcised before their eyes: and all that were born in his house; which were three hundred and eighteen when he rescued Lot...