Genesis 19:30-38

30 Lot 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. 31 The firstborn said to the younger, "Our father is old, and there is not a man in the earth to come in to us after the manner of all the earth. 32 Come, let's make our father drink wine, and we will lie with him, that we may preserve our father's seed." 33 They 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. 34 It came to pass on the next day, that the firstborn said to the younger, "Behold, I lay last night with my father. Let us make him drink wine again, tonight. You go in, and lie with him, that we may preserve our father's seed." 35 They made their father drink wine that night also. The younger arose, and lay with him. He didn't know when she lay down, nor when she arose. 36 Thus both of Lot's daughters were with child by their father. 37 The firstborn bore a son, and named him Moab. The same is the father of the Moabites to this day. 38 The younger also bore a son, and called his name Ben Ammi. The same is the father of the children of Ammon to this day.