וַתְּהִ֥י עָלַ֛י שָׁ֖ם יַד־יְהוָ֑ה וַיֹּ֣אמֶר אֵלַ֗י ק֥וּם צֵא֙ אֶל־הַבִּקְעָ֔ה וְשָׁ֖ם אֲדַבֵּ֥ר אוֹתָֽךְ׃
און די האַנט פֿון גאָט איז דאָרטן געװען אױף מיר, און ער האָט צו מיר געזאָגט: שטײ אױף, גײ אַרױס צום טאָל, און דאָרטן װעל איך רעדן מיט דיר.
Da'at Zekenim
בארץ מצרים, “in the land of Egypt.” Outside of the capital. If a conversation with G–d concerning a minor matter required Moses to leave the capital, as we know from Exodus 9,29, when something of major importance was to be discussed this required him to leave the capital of Egypt even more so.[This is all based on the extraneous words “in the land,” in our verse. It would have otherwise sufficed to simply write: “in Egypt.” Ed.] The reason why outside the capital of Egypt G–d would address Moses was that the land of Israel had not yet been chosen as the only area from which prophecy would be received. [When the first Temple was destroyed the prophet Ezekiel did receive prophetic visions as we know from Ezekiel 3,22. So did the prophet Jonah (Jonah 1,3) who had fled from the Holy Land. At any rate, as long as Jerusalem had not become the capital of Israel, G–d sometimes addressed prophets outside its boundaries. During those years sacrificial offerings were also acceptable outside Jerusalem. Moses’ warning in Deuteronomy 12,13, not to offer such offerings any place the owner of the animal chose to do so, was also not effective before the Temple stood in Jerusalem. The town itself was potentially on a spiritual level where prophetic visions could be received. As long as Aaron had not been appointed as High Priest, any area was potentially fit to serve as sovereign soil for the Jewish people under a king. These rules are derived from verses in Kings I 8,16, as well as from Chronicles II 13,5.
Rashi
בהיות הבקר lit., WHEN IT WAS BEING MORNING — This phrase tells us that He was there before them at the place of the Divine Revelation, something which it is not customary for human beings to do — that the teacher should await the arrival of his disciple. A similar instance we find in Scripture (Ezekiel 3:22, 23): “[God said unto me]. Arise, go forth into the plain, [and I will there speak with thee]. Then I arose, and went forth into the plain; and, behold the glory of the Lord stood there already” (Midrash Tanchuma, Ki Tisa 15; cf. Nedarim 8a).