Genesis 17:26 Meaning

24And Abraham was ninety years old and nine, when he was circumcised in the flesh of his foreskin.

25And Ishmael his son was thirteen years old, when he was circumcised in the flesh of his foreskin.

26In the selfsame day was Abraham circumcised, and Ishmael his son.

27And all the men of his house, born in the house, and bought with money of the stranger, were circumcised with him.