If one man sin against another, God shall judge him; but if a man sin against Yahweh, who shall entreat for him? Notwithstanding, they didn't listen to the voice of their father, because Yahweh was minded to kill them.
So the scene is set the man living in polygamy, two wives. One he loved more than the other. One had many children, but the one he really loved could not have any children.