And Moses said unto Hobab, the son of Raguel the Midianite, Moses’ father in law, We are journeying unto the place of which the Lord said, I will give it you: come thou with us, and we will do thee good: for the Lord hath spoken good concerning Israel. (Numbers 10:29)
This verse does not make it clear whether Hobab or Raguel was Moses’ father-in-law, for the word means merely an “in-law” of any sort. The context must determine each case. But Raguel (or Reuel) was the father-in-law (Ex. 2:16-21); hence his son Hobab was Moses’ brother-in-law (see PP 628).