Numbers 36:5-12

And Moses commanded the children of Israel according to the word of the LORD, saying, The tribe of the sons of Joseph hath said well.

Moses commanded ... according to the word of the Lord. The plea appeared just and reasonable; and accordingly an enactment was made by which the daughters of Zelophehad, while left to the free choice of their husbands, were restricted to marry not only within their own tribe, but within the family of their father's tribe - i:e., one of their cousins. This restriction, however, was imposed only on those who were heiresses. The law was not applicable to daughters in different circumstances (1 Chronicles 23:22). The great object of these two exceptional laws was, that the name of the man who died sonless should not be lost (Numbers 27:4); and on this account the person who married an heiress was called after the name of his father-in-law, and also of his own father, so that he had thus two family names (see the notes at 1 Chronicles 2:21; Nehemiah 7:63).

Jewish writers, however, say that this ordinance, interdicting the transference of lands from a family in one tribe to one of another, was binding only in the early period of their settlement in Canaan (Selden, 'De Synedriis,' lib. 4:, cap. 4:, n. 1; 'De Successione in Bona,' cap. xviii). Here was an instance of progressive legislation (see also Exodus 18:1; Numbers 27:1) in Israel, the enactments made being suggested by circumstances; but it is deserving of special notice that those additions to, or modifications of, the law were confined to civil affairs, while the slightest change was inadmissible in the laws relating to worship or the maintenance of religion.

The tribe of the sons of Joseph hath said well. "The tribe of Joseph" is the scriptural equivalent for the two tribes of Ephraim and Manasseh. In Numbers 13:11, "the tribe of Joseph" denotes Manasseh, as in this passage; while in Revelation 7:6; Revelation 7:8, it is applied to the greater tribe of Ephraim.