[1491 BC] Verse 1: Now Moses kept the flock of Jethro his father in law, (Ex. 2:16) the priest of Midian: and he led the flock to the backside of the desert, and came to (Ex. 18:5; 1 Kings 19:8) the mountain of God, even to Horeb.
[He was feeding] It is believed that here he had written the books of Genesis, and of Job for the solace of his own (Menochius).
[Jethro, his father-in-law, the priest of Midian] This Jethro was the same as Reuel, Exodus 2:18 (Oleaster, Lapide). He was rather the son of Reuel (Reuel, however, by this time appears to be dead, since forty years had passed, Exodus 2:18; Acts 7:30). Jethro is here called governor, because he succeeded his father in that dignity (Piscator, Ainsworth).
Jethro was either the same with Reuel, or his son, who, upon his father’s death, succeeded into his office. See Exodus 2:18.
[Unto more remote places of the desert, אַחַ֣ר הַמִּדְבָּ֔ר] Behind the desert (Pagnine), that is, into the innermost part of the desert (Vatablus, Rivet).
To the backside of the desert, to its innermost parts, which were behind Jethro’s habitation, and the former pastures, whither he went for fresh pastures.
[Unto the mountain of God] Horeb is so called, either, 1. because it was great and lofty, as in Psalme 36:6 (Ainsworth); or, 2. because of this vision (Junius, Piscator); or, 3. by anticipation, because there God was going to give the Law (Bonfrerius, Menochius, Lyra, Rivet).
The mountain of God; so called, either as a high or eminent mountain; or from the vision of God here following; see Acts 7:30; or by anticipation, from God’s glorious appearance there, and giving the law from thence, Exodus 18:5; 19:3: see also 1 Kings 19:8.
[Horeb] Which is also Sinai, Acts 7:30 (Ainsworth). Rather Horeb and Sinai are two peaks of the same mountain (Bonfrerius).
Horeb, called also Sinai, Exodus 19:1; Acts 7:30. Or Horeb was the name of the whole tract or row of mountains, and Sinai the name of that particular mountain where this vision happened, and the law was delivered. Or Horeb and Sinai were two several tops of the same mountain.
 Hebrew: וּמֹשֶׁ֗ה הָיָ֥ה רֹעֶ֛ה אֶת־צֹ֛אן יִתְר֥וֹ חֹתְנ֖וֹ כֹּהֵ֣ן מִדְיָ֑ן וַיִּנְהַ֤ג אֶת־הַצֹּאן֙ אַחַ֣ר הַמִּדְבָּ֔ר וַיָּבֹ֛א אֶל־הַ֥ר הָאֱלֹהִ֖ים חֹרֵֽבָה׃
 Hebrew: כֹּהֵן, priest or prince.
 Psalm 36:6a: “Thy righteousness is like the great mountains (כְּהַרְרֵי־אֵל, the mountains of God); thy judgments are a great deep…”