And they made their father drink wine that night. And the firstborn went in, and lay with her father. And he did not know when she lay down, nor when she arose.
And it came to pass on the morrow, that the firstborn said to the younger, Behold, I lay last night with my father. Let us make him drink wine this night also, and go thou in, and lay with him, that we may preserve seed by our fath