17:15And God said unto Abraham, As for Sarai thy wife, thou shalt not call her name Sarai, but Sarah shall her name be.
17:16And I will bless her, and give thee a son also of her: yea, I will bless her, and she shall be a mother of nations; kings of people shall be of her.
17:17Then Abraham fell upon his face, and laughed, and said in his heart, Shall a child be born unto him that is an hundred years old? and shall Sarah, that is ninety years old, bear?
17:18And Abraham said unto God, O that Ishmael might live before thee!
17:19And 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.
17:20And as for Ishmael, I have heard thee: Behold, I have blessed him, and will make him fruitful, and will multiply him exceedingly; twelve princes shall he beget, and I will make him a great nation.
17:21But my covenant will I establish with Isaac, which Sarah shall bear unto thee at this set time in the next year.
18:9And they said unto him, Where is Sarah thy wife? And he said, Behold, in the tent.
18:10And he said, I will certainly return unto thee according to the time of life; and, lo, Sarah thy wife shall have a son. And Sarah heard it in the tent door, which was behind him.
18:11Now Abraham and Sarah were old and well stricken in age; and it ceased to be with Sarah after the manner of women.
18:12Therefore Sarah laughed within herself, saying, After I am waxed old shall I have pleasure, my lord being old also?
18:13And the LORD said unto Abraham, Wherefore did Sarah laugh, saying, Shall I of a surety bear a child, which am old?
18:14Is any thing too hard for the LORD? At the time appointed I will return unto thee, according to the time of life, and Sarah shall have a son.
18:15Then Sarah denied, saying, I laughed not; for she was afraid. And he said, Nay; but thou didst laugh.