Exodus 3:1
ESV - 1 Now Moses was keeping the flock of his father-in-law, Jethro, the priest of Midian, and he led his flock to the west side of the wilderness and came to Horeb, the mountain of God.
For follow-up discussion and general commentary on the topic. Comments are sorted chronologically.
My opinion is that REUEL mentioned in Num 10 v 29 is not the same REUEL mentioned or/and identified as JETHRO in the book of Exodus.
REUEL/JETHRO of Exodus has seven daughters but no son while REUEL of Numbers 10 v 29 has son (HOBAB)
In my opinion, there are two possible ways of reconciling this. Exodus 2:16 says that Jethro (Reuel) had seven daughters, but it does not explicitly say that he had no sons (although the verse does not mention them). Alternatively, Hobab may have been the husband of one of Reuel's daughters (other than Zipporah, whom Moses married), and thus would have been the son-in-law (although not biological son) of Reuel, and Moses' brother-in-law.