Unto Machir, i.e. not to Machir himself, who doubtless was long since dead; see Genesis 1:23; but the family or posterity of Machir, which are called by their father's name; as the names of Abraham, Acts 7:16; of Isaac, Amos 7:9; of Jacob or Israel frequently; of Judah and Simeon, Judges 1:3; of David, 1 Kings 12:16; are manifestly put for their posterity.
Related Commentaries of Numbers 32:40
Numbers 32:40
40 And Moses gave Gilead unto Machir the son of Manasseh; and he dwelt therein.