Genesis 19:32

30Lot went up out of Zoar, and lived in the mountain, and his two daughters with him; for he was afraid to live in Zoar. He lived in a cave with his two daughters.

31The firstborn said to the younger, “Our father is old, and there is not a man on the earth to come in to us in the way of all the earth.

32Come, let’s make our father drink wine, and we will lie with him, that we may preserve our father’s family line.”

33They made their father drink wine that night: and the firstborn went in, and lay with her father. He didn’t know when she lay down, nor when she arose.

34It came to pass on the next day, that the firstborn said to the younger, “Behold, I lay last night with my father. Let’s make him drink wine again tonight. You go in, and lie with him, that we may preserve our father’s family line.”