Exodus 3:1

But Mosheh was keeping the flock of Jethro his father-in-law, the rabba of Midian; and he had led the flock to a pleasant place of pasturage which is behind the desert, and had come to the mountain on which was revealed the glory of the Lord, even Horeb.

"To Horeb, the mountain of God"—Thus wrote Moses. And the reason it is "Horeb" (i.e. dry) is because of the great heat, for rain did not fall there, because it was close to Egypt, [only] a three day's walk, as Moses spoke. And because the Nile was far away, there was no moisture there, and the dryness prevailed.

MOSES, TENDING THE FLOCK ETC. The Holy One, blessed be He, appeared to him and commanded him to return to Egypt, and Moshe did not want to do so, because he was afraid until the Holy One, blessed be He, told him, "all the men who sought to kill you are dead" -- this is Par'oh, who had died. That is why it says (Exod. 2:23), "the king of Egypt died," to testify to what the Holy One, blessed be He, said, that "all the men ... are dead." This is similar to (Gen. 9:18) "Ham being the father of Canaan."

ויבא אל הר האלוקים חורבה. Moses, all by himself; he wanted to pray and meditate there in complete isolation and concentration. The phrase is similar to Numbers 13,22 ויבא עד חברון, where we find that one of the spies, Calev, reportedly, came to Chevron. [the sudden singular ויבא instead of ויבואו, there prompted the sages to say that Calev went to pray at the graves of the patriarchs. Ed.]

וינהג את הצאן, “he led the flock after the desert.” The choice of the word אחר here is to serve as a hint that when G–d’s flock in the desert, i.e. the generation that left Egypt as adults had all died, and he had been buried where they had been buried, in the desert, He could bring the next generation to the land of Israel right away; this is why the verse ends with describing the mountain where Moses stood as being already “the Mountain of G–d.”