Genesis 17:25-27

17:25 his son Ishmael was thirteen years old ¹  when he was circumcised. 17:26 Abraham and his son Ishmael were circumcised on the very same day. 17:27 All the men of his household, whether born in his household or bought with money from a foreigner, were circumcised with him.

[17:25]  ¹ tn Heb “the son of thirteen years.”