5 If brothers are living together and one of them dies without a son, his widow must not marry outside the family. Her husband's brother shall take her and marry her and fulfill the duty of a brother-in-law to her. 6 The first son she bears shall carry on the name of the dead brother so that his name will not be blotted out from Israel.
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.
5 "If brothers dwell together, and one of them dies and has no son, the wife of the dead man shall not be married outside the family to a stranger. Her husband's brother shall go in to her and take her as his wife and perform the duty of a husband's brother to her. 6 And the first son whom she bears shall succeed to the name of his dead brother, that his name may not be blotted out of Israel.
5 When brothers are living together and one of them dies without having had a son, the widow of the dead brother shall not marry a stranger from outside the family; her husband's brother is to come to her and marry her and do the brother-in-law's duty by her. 6 The first son that she bears shall be named after her dead husband so his name won't die out in Israel.
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. 6 And it shall be that the firstborn son which she bears will succeed to the name of his dead brother, that his name may not be blotted out of Israel.
5 "If two brothers are living together on the same property and one of them dies without a son, his widow may not be married to anyone from outside the family. Instead, her husband's brother should marry her and have intercourse with her to fulfill the duties of a brother-in-law. 6 The first son she bears to him will be considered the son of the dead brother, so that his name will not be forgotten in Israel.
Matthew Henry's Commentary on Deuteronomy 25:5-6
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.