23 On that very day Abraham took his son, Ishmael, and every male in his household, including those born there and those he had bought. Then he circumcised them, cutting off their foreskins, just as God had told him. 24 Abraham was ninety-nine years old when he was circumcised, 25 and Ishmael, his son, was thirteen. 26 Both Abraham and his son, Ishmael, were circumcised on that same day, 27 along with all the other men and boys of the household, whether they were born there or bought as servants. All were circumcised with him.
Matthew Henry's Commentary on Genesis 17:23-27
Commentary on Genesis 17:23-27
(Read Genesis 17:23-27)
Abraham 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. It was an implicit obedience; he did as God said unto him, and did not ask why or wherefore. He did it because God bade him. It was a speedy obedience; in the self-same day. Sincere obedience makes no delay. Not only the doctrines of revelation, but the seals of God's covenant, remind us that we are guilty, polluted sinners. They show us our need of the blood of atonement; they point to the promised Saviour, and teach us to exercise faith in him. They show us that without regeneration, and sanctification by his Spirit, and the mortification of our corrupt and carnal inclinations, we cannot be in covenant with God. But let us remember that the true circumcision is that of the heart, by the Spirit, Romans 2:28,29. Both under the old and new dispensation, many have had the outward profession, and the outward seal, who were never sealed by the Holy Spirit of promise.