Deuteronomy 25:5
5 "If brothers dwell together, and one of them dies and has no son, the widow of the dead man shall not be married to a stranger outside the family; her husband's brother shall go in to her, take her as his wife, and perform the duty of a husband's brother to her.
Scripture taken from the New King James Version. Copyright © 1982 by Thomas Nelson, Inc. Used by permission. All rights reserved.
Matthew Henry's Commentary on Deuteronomy 25:5
Commentary on Deuteronomy 25:5-12
(Read Deuteronomy 25:5-12)
The custom here regulated seems to have been in the Jewish law in order to keep inheritances distinct; now it is unlawful.