(א) וַיְדַבֵּ֨ר יְהוָ֧ה אֶל־מֹשֶׁ֛ה בְּמִדְבַּ֥ר סִינַ֖י בְּאֹ֣הֶל מוֹעֵ֑ד בְּאֶחָד֩ לַחֹ֨דֶשׁ הַשֵּׁנִ֜י בַּשָּׁנָ֣ה הַשֵּׁנִ֗ית לְצֵאתָ֛ם מֵאֶ֥רֶץ מִצְרַ֖יִם לֵאמֹֽר׃ (ב) שְׂא֗וּ אֶת־רֹאשׁ֙ כָּל־עֲדַ֣ת בְּנֵֽי־יִשְׂרָאֵ֔ל לְמִשְׁפְּחֹתָ֖ם לְבֵ֣ית אֲבֹתָ֑ם בְּמִסְפַּ֣ר שֵׁמ֔וֹת כָּל־זָכָ֖ר לְגֻלְגְּלֹתָֽם׃
(1) וידבר… במדבר סיני … באחד לחדש וגו׳ AND [THE ETERNAL] SPOKE [TO MOSES] IN THE DESERT OF SINAI … ON THE FIRST DAY OF THE [SECOND] MONTH … [TAKE THE SUM OF ALL THE CONGREGATION] etc. — Because they were dear to him, He counts them every now and then: when they went forth from Egypt He counted them (Exodus 12:37), when many of them fell in consequence of their having worshipped the golden calf He counted them to ascertain the number of those left (cf. Rashi Exodus 30:16); when he was about to make His Shechinah dwell amongst them (i. e. when He commanded them to make a Tabernacle), He again took their census; for on the first day of Nisan the Tabernacle was erected (Exodus 40:2) and shortly afterwards, on the first day of Iyar, He counted them.
החל לפרש על הפשט ספר וידבר במדבר סיני. להודיע כי לא עלה משה אל הר סיני אחר היות הכבוד באהל מועד
...[The language of] In the wilderness of Sinai is to indicate that Moses did not go up on Mt. Sinai after the Presence [of God] came to be in the Tent of Meeting.
(18) The well which the chieftains dug, Which the nobles of the people started With maces, with their own staffs. And from Midbar to Mattanah, (19) and from Mattanah to Nahaliel, and from Nahaliel to Bamoth ...
In the wilderness of Mattanah. If he is like a "wilderness", Torah is given in a gift (mattana), and will forget it.
Rabbi Menachem Mendel of Kotzk
Only when you are "like a wilderness" are you ready to have God's presence rest upon you and merit the light of Torah. "Like a wilderness" means that you have not yet been touched by human hands, that you have never been cultivated or planted, that you must rely on your own strength, as in the teaching, "If I am not for myself, who will be for me?" (Mishnah Avot 1:14).
Itturei Torah [Hebrew], vol. 5, by Aharon Yaakov Greenberg [Tel Aviv: Yavneh, 1996], p. 9