Bible Dictionary
HUSBAND'S BROTHER
A husband’s brother, or levir, was expected under Israelite law to marry his deceased brother’s childless widow and raise up offspring for the dead brother. Refusal brought public disgrace, though the duty could be declined.
Biblical Usage
Deuteronomy 25:5-10 and Matthew 22:24 refer to this duty. Refusal was possible but brought public ceremonial disgrace and lasting reproach. The custom appears in the account of Judah and Tamar and is alluded to in Ruth. Boaz in Ruth 4 acted as redeemer rather than as the levir.