1 Chronicles 1:28
Abraham's descendants were Isaac and Ishmael.
Genesis 16:11-16
"Look, you are pregnant and will give birth to a son," the angel of the LORD continued to say to her. "You will name him Ishmael, because the LORD has heard your cry of misery.
Genesis 17:19-21
But God replied, "No, but your wife Sarah will give birth to your son, and you are to name him Isaac. I'll confirm my covenant with him as an eternal covenant for his descendants.
Genesis 21:2-5
Sarah conceived and gave birth to a son for Abraham in his old age, at the very time that God had told him.
Genesis 21:9-10
Nevertheless, when Sarah saw the son of Hagar the Egyptian whom Hagar had borne to Abraham making fun of Isaac,
Genesis 21:12
but God told Abraham, "Don't be troubled about the youth and your slave girl. Pay attention to Sarah in everything she tells you, because your offspring are to be named through Isaac.