Hebrews 11:18
to whom it was said, “Through Isaac your descendants shall be called.”
Genesis 21:12
God said to Abraham, “Do not let it distress you because of Ishmael and your maid; whatever Sarah tells you, listen to her and do what she asks, for your descendants will be named through Isaac.
Romans 9:7
and they are not all the children of Abraham because they are his descendants [by blood], but [the promise was]: “Your descendants will be named through Isaac” [though Abraham had other sons].
Genesis 17:19
But God said, “No, Sarah your wife shall bear you a son indeed, and you shall name him Isaac (laughter); and I will establish My covenant with him for an everlasting covenant and with his descendants after him.