TSK · Ruth 3:2

If brothers dwell together, and one of them die, and have no son, the wife of the dead shall not be married outside to a stranger: her husband's brother shall go in to her, and take her to him as wife, and perform the duty of a husband's brother to her.

Then Boaz said to Ruth, "Listen, my daughter. Don't go to glean in another field, and don't go from here, but stay here close to my maidens.

For both he who sanctifies and those who are sanctified are all from one, for which cause he is not ashamed to call them brothers,