Exodus 3:1 Now Moses kept the flock of Jethro his father in law, the priest of Midian: and he led the flock to the backside of the desert, and came to the mountain of God, even to Horeb. - Free Bible Online

      Ex 3:1-22. DIVINE APPEARANCE AND COMMISSION TO MOSES.

      1. Now Moses kept the flock--This employment he had entered on in furtherance of his matrimonial views (see on Ex 2:21), but it is probable he was continuing his service now on other terms like Jacob during the latter years of his stay with Laban (Ge 30:28).
      he led the flock to the backside of the desert--that is, on the west of the desert [GESENIUS], assuming Jethro's headquarters to have been at Dahab. The route by which Moses led his flock must have been west through the wide valley called by the Arabs, Wady-es-Zugherah [ROBINSON], which led into the interior of the wilderness.
      Mountain of God--so named either according to Hebrew idiom from its great height, as "great mountains," Hebrew, "mountains of God" (Ps 36:6); "goodly cedars," Hebrew, "cedars of God" (Ps 80:10); or some think from its being the old abode of "the glory"; or finally from its being the theater of transactions most memorable in the history of the true religion to Horeb--rather, "Horeb-ward."
      Horeb--that is, "dry," "desert," was the general name for the mountainous district in which Sinai is situated, and of which it is a part. (See on Ex 19:2). It was used to designate the region comprehending that immense range of lofty, desolate, and barren hills, at the base of which, however, there are not only many patches of verdure to be seen, but almost all the valleys, or wadys, as they are called, show a thin coating of vegetation, which, towards the south, becomes more luxuriant. The Arab shepherds seldom take their flocks to a greater distance than one day's journey from their camp. Moses must have gone at least two days' journey, and although he seems to have been only following his pastoral course, that region, from its numerous springs in the clefts of the rocks being the chief resort of the tribes during the summer heats, the Providence of God led him thither for an important purpose.

JFB.