Then Judah said to Er's brother Onan, “Go and sleep with your brother's widow. Fulfill your obligation to her as her husband's brother, so that your brother may have descendants.”
The older daughter said to her sister, “Our father is getting old, and there are no men in the whole world to marry us so that we can have children.
or with your brother's wife.
“You must go back, my daughters,” Naomi answered. “Why do you want to come with me? Do you think I could have sons again for you to marry?