Genesis 17:12

Overview - Genesis 17
God renews the covenant with Abram, and changes his name to Abraham, in token of a greater blessing.
Circumcision is instituted.
15 Sarai's name is changed to Sarah, and she is blessed.
17 Isaac is promised, and the time of his birth fixed.
23 Abraham and Ishmael are circumcised.
Treasury of Scripture Knowledge

Genesis 17:12  (King James Version)
And he that is eight days old shall be circumcised among you, every man child in your generations, he that is born in the house, or bought with money of any stranger, which is not of thy seed.

he that is eight days old
Hebrew a son of eight days.
21:4 Leviticus 12:3 ; Luke 1:59 ; 2:21 John 7:22 John 7:23 ; Acts 7:8 ; Romans 2:28 ; Philippians 3:5

is born
23 ; Exodus 12:48 Exodus 12:49