22 For it is written that Abraham had two sons, one from the servant girl, and one from the freewoman.
Galatians 4:22 Cross References - ACV
Genesis 16:2-4
2 And Sarai said to Abram, Behold now, LORD has restrained me from bearing. Go in, I pray thee, to my handmaid. It may be that I will obtain sons by her. And Abram hearkened to the voice of Sarai.
3 And Sarai, Abram's wife, took Hagar the Egyptian, her handmaid, after Abram had dwelt ten years in the land of Canaan, and gave her to Abram her husband to be his wife.
4 And he went in to Hagar, and she conceived. And when she saw that she had conceived, her mistress was despised in her eyes.
Genesis 16:15
15 And Hagar bore Abram a son. And Abram called the name of his son, whom Hagar bore, Ishmael.
Genesis 21:1-2
Genesis 21:10
10 Therefore she said to Abraham, Cast out this handmaid and her son. For the son of this handmaid shall not be heir with my son, even with Isaac.