Charles Ellicott Commentary Exodus 3:1

"Now Moses was keeping the flock of Jethro his father-in-law, the priest of Midian: and he led the flock to the back of the wilderness, and came to the mountain of God, unto Horeb." — Exodus 3:1 (ASV)

Moses kept the flock. —The natural occupation of one who had thrown in his lot with the Midianites.

Jethro, his father-in-law. —Rather, his relation by marriage. The word is one of very wide use, corresponding with the Latin affinis. It is even applied to a husband, as in Exodus 4:25.

The supposition that it means “father-in-law” has led to the identification of Jethro with Reuel, which is very unlikely. He was more probably Reuel’s son and Moses’s brother-in-law. His father having died, he had succeeded to his father’s position and was at once priest and sheikh of the tribe.

To the backside of the desert. —Hebrew, behind the desert — that is, to the fertile tract which lay behind the sandy plain stretching from the Sinaitic range to the shore of the Elanitic gulf.

The mountain of God — that is, Sinai. See Exodus 18:5; Exodus 19:2–23, and other passages.

Even Horeb. —Rather, towards Horeb, or in the direction of Horeb. Horeb seems to have been the name of the entire mountain region; Sinai, that of the group or mass known now as Jebel Musa.