Genesis 18:10-13

Then one of them said, “I will surely return to you about this time next year, and Sarah your wife will have a son.” Now Sarah was listening at the entrance to the tent, which was behind him. Abraham and Sarah were already very old, and Sarah was past the age of childbearing. So Sarah laughed to herself as she thought, “After I am worn out and my lord is old, will I now have this pleasure?” Then the LORD said to Abraham, “Why did Sarah laugh and say, ‘Will I really have a child, now that I am old?’