Genesis 17:25

New King James Version

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

Cross References

Genesis 16:16

Abram was eighty-six years old when Hagar bore Ishmael to Abram.

Genesis 17:26

That very same day Abraham was circumcised, and his son Ishmael;

Genesis 16:15

So Hagar bore Abram a son; and Abram named his son, whom Hagar bore, Ishmael.