C. F. Keil and Franz Delitzsch on Numbers 32:41

Num 32:41

The family of Manasseh named after Machir included “Jair the son (i.e., descendant) of Manasseh.” Jair, that is to say, was the grandson of a daughter of Machir the son of Manasseh, and therefore a great-grandson of Manasseh on the mother’s side. His father Segub was the son of Hezron of the tribe of Judah, who had married a daughter of Manasseh (1Ch 2:21-22); so that Jair, or rather Segub, had gone over with his descendants into the maternal tribe, contrary to the ordinary rule, and probably because Machir had portioned his daughter with a rich dowry like an heiress. Jair took possession of the whole of the province of Argob in Bashan, i.e., in the plain of Jaulan and Hauran (Deu 3:4 and Deu 3:14), and gave the conquered towns the name of Havvoth Jair, i.e., Jair's-lives (see at Deu 3:14).