Jamieson, Fausset and Brown on Numbers 10:29

29. Hobab, the son of Raguel the Midianite--called also Reuel (the same as Jethro [Ex 2:18, Margin]). Hobab, the son of this Midianite chief and brother-in-law to Moses, seems to have sojourned among the Israelites during the whole period of their encampment at Sinai and now on their removal proposed returning to his own abode. Moses urged him to remain, both for his own benefit from a religious point of view, and for the useful services his nomad habits could enable him to render.