Deuteronomy 25:5

“If brethren dwell together, etc.] Not only in the same country, province, town, or city, but in the same house; such who had been from their youth brought up together in their father’s house, and now one of them being married, as the case put supposes, they that were unmarried might live with him, and especially if the father was dead; and so may except such as were abroad, and in foreign countries, or at such a distance that this law coals not well be observed by them; though the Targum of Jonathan, and so Jarchi, interpret it of their being united in an inheritance, all by virtue of relation having a claim to their father’s inheritance; so that it mattered not where they dwelt, it is the…”

“the wife of the dead shall not marry without unto a stranger: her husband's brother . . . shall take her to him to wife--This usage existed before the age of Moses (Gen 38:8). But the Mosaic law rendered the custom obligatory (Mat 22:25) on younger brothers, or the nearest kinsman, to marry the widow (Rut 4:4), by associating the natural desire of perpetuating a brother's name with the preservation of property in the Hebrew families and tribes. If the younger brother declined to comply with the law, the widow brought her claim before the authorities of the place at a public assembly (the gate of the city); and he having declared his refusal, she was ordered to loose the thong of his shoe--a…”

“The law of levirate marriage. The law on this subject is not unique to the Jews, but is found (see Genesis 38:8) in all essential respects the same among various Oriental nations, ancient and modern. The rules in these verses, like those upon divorce, do but incorporate existing immemorial usages, and introduce various wise and politic limitations and mitigations of them. The root of the obligation here imposed upon the brother of the deceased husband lies in the primitive idea of childlessness being a great calamity (compare Genesis 16:4; and note), and extinction of name and family one of the greatest that could happen (compare Deuteronomy 9:14; Psalms 109:12-15). To avert this the…”

“Together - In the same town, or at least country. For if the next brother had removed his habitation into remote parts, on were carried thither into captivity, then the wife of the dead had her liberty to marry the next kinsman that lived in the same place with her. One - Any of them, for the words are general, and the reason of the law was to keep up the distinction of tribes and families, that so the Messiah might be discovered by the family from which he was appointed to proceed; and also of inheritances, which were divided among all the brethren, the first - born having only a double portion. A stranger - To one of another family. Deuteronomy 25:6”

“25:5 The term rendered duties of a brother-in-law refers to the levirate (Latin for brother-in-law) marriage custom. The brother of a deceased man was encouraged to marry his brother’s widow and father her children so that the name of the dead brother would not be forgotten. For examples of this custom, see Gen 38:6-11; Ruth 3:12-13; 4:1-12; Luke 20:27-33.”

“brethren: Mat 22:24; Mar 12:19; Luk 20:28 husband's brother: or, next kinsman, Gen 38:8, Gen 38:9; Rut 1:12, Rut 1:13, Rut 3:9, Rut 4:5 Deuteronomy 25:6”

“On Levirate Marriages. - Deu 25:5, Deu 25:6. If brothers lived together, and one of them died childless, the wife of the deceased was not to be married outside (i.e., away from the family) to a strange man (one not belonging to her kindred); her brother-in-law was to come to her and take her for his wife, and perform the duty of a brother-in-law to her. יבּם, denom. from יבם, a brother-in-law, husband's brother, lit., to act the brother-in-law, i.e., perform the duty of a brother-in-law, which consisted in his marrying his deceased brother's widow, and begetting a son of children with her, the first-born of whom was "to stand upon the name of his deceased brother," i.e., be placed in the…”