Genesis 18:10-14

Then the LORD said, “I will certainly return to you about this time a year from now. At that time your wife Sarah will have a son.” Sarah was listening at the entrance of the tent which was behind him. Abraham and Sarah were very old. Since Sarah was past the age when women normally have children, she laughed to herself, “My husband and I are too old to have a baby.” Then the LORD said to Abraham, “Why did Sarah laugh? Why did she say, ‘I am too old to have a baby’? Is anything too hard for the LORD? No! I will return to you at the right time a year from now, and Sarah will have a son.”