And he that is eight days old—literally, and the son of eight days (cf. Genesis 17:1)—shall be circumcised among you (Le Genesis 12:3; Luke 2:21; Philippians 3:5), every man child—"The fact that several times the circumcision of the males only is enjoined may point to the legislator's intention to exclude that rite in the other sex, though it was customary among many ancient nations, but not universal among the Egyptians" (Kalisch).
Though not administered to both, the symbol was ordained for the sake of both sexes (Calvin)—in your generations, he that is born in the house, or bought with money of any stranger, which is not of thy seed.
Not only a proof of the Divine benignity to Abraham in embracing all the members of his household within the pale of the visible Church now constituted, but likewise a hint of the world-wide aspect of the Abrahamic covenant, a first-fruits as it were of the "all the families of the earth" that should be blessed in Abram.