Genesis 19:31-33

And the older daughter said to her sister, Our father is old, and there is no man to be a husband to us in the natural way: Come, let us give our father much wine, and we will go into his bed, so that we may have offspring by our father, And that night they made their father take much wine; and the older daughter went into his bed; and he had no knowledge of when she went in or when she went away.