Then said Judah to Tamar his daughter-in-law, Remain a widow at your father's house, till Shelah my son is grown: for he said, Lest perhaps he die also, as his brothers did. And Tamar went and dwelt in her father's house.
And Onan knew that the descendant would not be his; and it came to pass, when he went in unto his brother's wife, that he spilled it on the ground, lest that he should give a descendant to his brother.
If brethren dwell together, and one of them dies, and has no child, the wife of the dead shall not marry outside unto a stranger: her husband's brother shall go in unto her, and take her to him as wife, and perform the duty of a husband's brother unto her.
Turn again, my daughters, go your way; for I am too old to have a husband. If I should say, I have hope, if I should have a husband also tonight, and should also bear sons;