Genesis 17:19-21

And God said, Sarah thy wife shall bear thee a son indeed; and thou shalt call his name Isaac: and I will establish my covenant with him for an everlasting covenant, {and} with his seed after him.

Genesis 21:2-5

For Sarah conceived, and bare Abraham a son in his old age, at the set time of which God had spoken to him.

Genesis 21:12

And God said unto Abraham, Let it not be grievous in thy sight because of the lad, and because of thy bondwoman; in all that Sarah hath said unto thee, hearken unto her voice; for in Isaac shall thy seed be called.

Genesis 16:11-16

And the angel of the LORD said unto her, Behold, thou {art} with child, and shalt bear a son, and shalt call his name Ishmael; because the LORD hath heard thy affliction. {Ishmael: that is, God shall hear}

Genesis 21:9-10

And Sarah saw the son of Hagar the Egyptian, which she had born unto Abraham, mocking.