Charles Ellicott Commentary Exodus 18:27

"And Moses let his father-in-law depart; and he went his way into his own land." — Exodus 18:27 (ASV)

Moses let his father-in-law depart. —Heb. Moses dismissed his connection. The supposed identity of Hobab (Numbers 10:29; Judges 4:11) with Jethro seems precluded by this statement, for Hobab clearly remained with Moses till the close of the stay at Sinai, and Moses, instead of “dismissing” him, was most unwilling that he should depart.