Thematic Bible: Her miraculous conception of isaac

God said to Abraham, "As for Sarai your wife, you shall not call her name Sarai, but her name will be Sarah. I will bless her, and moreover I will give you a son by her. Yes, I will bless her, and she will be a mother of nations. Kings of peoples will come from her." Then Abraham fell on his face, and laughed, and said in his heart, "Will a child be born to him who is one hundred years old? Will Sarah, who is ninety years old, give birth?" read more.
Abraham said to God, "Oh that Ishmael might live before you!" God said, "No, but Sarah, your wife, will bear you a son. You shall call his name Isaac. I will establish my covenant with him for an everlasting covenant for his seed after him. As for Ishmael, I have heard you. Behold, I have blessed him, and will make him fruitful, and will multiply him exceedingly. He will become the father of twelve princes, and I will make him a great nation. But my covenant I establish with Isaac, whom Sarah will bear to you at this set time next year."

They asked him, "Where is Sarah, your wife?" He said, "See, in the tent." He said, "I will certainly return to you when the season comes round. Behold, Sarah your wife will have a son." Sarah heard in the tent door, which was behind him. Now Abraham and Sarah were old, well advanced in age. Sarah had passed the age of childbearing. read more.
Sarah laughed within herself, saying, "After I have grown old will I have pleasure, my lord being old also?" Yahweh said to Abraham, "Why did Sarah laugh, saying, 'Will I really bear a child, yet I am old?' Is anything too hard for Yahweh? At the set time I will return to you, when the season comes round, and Sarah will have a son." Then Sarah denied, saying, "I didn't laugh," for she was afraid. He said, "No, but you did laugh."