Genesis 19:33-38 ▼

33 So they made their father drink wine that night; and the firstborn went in, and lay with her father; he did not know when she lay down or when she rose.

34 On the next day, the firstborn said to the younger, “Look, I lay last night with my father; let us make him drink wine tonight also; then you go in and lie with him, so that we may preserve offspring through our father.”

35 So they made their father drink wine that night also; and the younger rose, and lay with him; and he did not know when she lay down or when she rose.

36 Thus both the daughters of Lot became pregnant by their father.

37 The firstborn bore a son, and named him Moab; he is the ancestor of the Moabites to this day.

38 The younger also bore a son and named him Ben-ammi; he is the ancestor of the Ammonites to this day.