Genesis 18:7-11

Abraham also ran to the herd, and took a tender and choice calf and gave it to the servant, and he hurried to prepare it.

He took curds and milk and the calf which he had prepared, and set it before them; and he was standing by them under the tree as they ate.

Then they said to him, “Where is your wife Sarah?” And he said, “There, in the tent.”

He said, “I will certainly return to you at this time next year; and behold, your wife Sarah will have a son.” And Sarah was listening at the tent door, which was behind him.

Now Abraham and Sarah were old, advanced in age; Sarah was past childbearing.