Albert Barnes Commentary Numbers 10:29

"And Moses said unto Hobab, the son of Reuel the Midianite, Moses` father-in-law, We are journeying unto the place of which Jehovah said, I will give it you: come thou with us, and we will do thee good; for Jehovah hath spoken good concerning Israel." — Numbers 10:29 (ASV)

Hobab, the son of Raguel—or Reuel (Exodus 2:18). Reuel was probably not identical with Jethro. And Hobab was the brother-in-law, not the father-in-law, of Moses; the Hebrew word translated in the King James Version “father-in-law,” signifying simply any relation by marriage (Exodus 3:1 note). Hobab (Judges 1:16; Judges 4:11) eventually accompanied the Israelites and obtained a settlement with them in the land of Canaan. Hobab and Jethro may have been brethren and sons of Reuel.