Genesis 19:34

The next day , the firstborn said to the younger , Behold , I lay last night with my father . Let us make him drink wine tonight also . Then you go in and lie with him, that we may preserve offspring from our father .

The next day the older daughter said to the younger, “Last night I slept with my father. Let`s get him to drink wine again tonight, and you go in and sleep with him so we can preserve our family line through our father.”

And it came to pass on the morrow, that the firstborn said unto the younger, Behold, I lay yesternight with my father : let us make him drink wine this night also; and go thou in, and lie with him, that we may preserve seed of our father.