If
Genesis 38:8
And Judah said unto Onan, Go in unto thy brother's wife, and marry her, and raise up seed to thy brother.
Deuteronomy 25:5-10
5
If brethren dwell together, and one of them die, and have no child, the wife of the dead shall not marry without unto a stranger: her husband's brother shall go in unto her, and take her to him to wife, and perform the duty of an husband's brother unto her.
6
And it shall be, that the firstborn which she beareth shall succeed in the name of his brother which is dead, that his name be not put out of Israel.
7
And if the man like not to take his brother's wife, then let his brother's wife go up to the gate unto the elders, and say, My husband's brother refuseth to raise up unto his brother a name in Israel, he will not perform the duty of my husband's brother.
8
Then the elders of his city shall call him, and speak unto him: and if he stand to it, and say, I like not to take her;
9
Then shall his brother's wife come unto him in the presence of the elders, and loose his shoe from off his foot, and spit in his face, and shall answer and say, So shall it be done unto that man that will not build up his brother's house.
10
And his name shall be called in Israel, The house of him that hath his shoe loosed.
Ruth 4:5
Then said Boaz, What day thou buyest the field of the hand of Naomi, thou must buy it also of Ruth the Moabitess, the wife of the dead, to raise up the name of the dead upon his inheritance.
that
Ruth 1:11-13
11
And Naomi said, Turn again, my daughters: why will ye go with me? are there yet any more sons in my womb, that they may be your husbands?
12
Turn again, my daughters, go your way; for I am too old to have an husband. If I should say, I have hope, if I should have an husband also to night, and should also bear sons;
13
Would ye tarry for them till they were grown? would ye stay for them from having husbands? nay, my daughters; for it grieveth me much for your sakes that the hand of the LORD is gone out against me.