Thematic Bible: Her miraculous conception of isaac

God continued: Do not call your wife Sarai any longer. Her name will be Sarah. I will bless her and will surely give you a son by her. I will bless her so that she will be the mother of nations. Kings of peoples will come from her. Abraham fell to his face. He laughed and said to himself: Will a son be born to a man a hundred years old? Will Sarah bear a child at the age of ninety? read more.
Abraham said to God: If only Ishmael might live under your blessing! God replied: Yes, but your wife Sarah will bear you a son! You will call him Isaac. I will establish my covenant with him as a long lasting covenant for his descendants after him. Concerning Ishmael, I have heard you: I will surely bless him. I will make him fruitful and will greatly increase his numbers. He will be the father of twelve rulers, and I will make him into a great nation. But my covenant I will establish with Isaac. Sarah will bear him to you by this time next year.

Then they said to him: Where is Sarah your wife? He responded: Here, in the tent. He said: Next year I will give you and Sarah a son. (Sarah was listening in the tent door behind him.) Abraham and Sarah were old, well advanced in age. Sarah had passed the age of childbearing. read more.
Therefore Sarah laughed within herself. She said to herself: After I have grown old, shall I have a baby? My lord is old also. Jehovah said to Abraham: Why did Sarah laugh, saying, 'Shall I surely bear a child, since I am old?' Is anything too hard for Jehovah? At the appointed time I will return to you, according to the time of life. Sarah shall have a son! Sarah denied saying: I did not laugh! She was afraid. He said: But you did laugh!