(א) וַיְדַבֵּ֨ר יהוה אֶל־מֹשֶׁ֛ה בְּמִדְבַּ֥ר סִינַ֖י בְּאֹ֣הֶל מוֹעֵ֑ד בְּאֶחָד֩ לַחֹ֨דֶשׁ הַשֵּׁנִ֜י בַּשָּׁנָ֣ה הַשֵּׁנִ֗ית לְצֵאתָ֛ם מֵאֶ֥רֶץ מִצְרַ֖יִם לֵאמֹֽר׃ (ב) שְׂא֗וּ אֶת־רֹאשׁ֙ כׇּל־עֲדַ֣ת בְּנֵֽי־יִשְׂרָאֵ֔ל לְמִשְׁפְּחֹתָ֖ם לְבֵ֣ית אֲבֹתָ֑ם בְּמִסְפַּ֣ר שֵׁמ֔וֹת כׇּל־זָכָ֖ר לְגֻלְגְּלֹתָֽם׃ (ג) מִבֶּ֨ן עֶשְׂרִ֤ים שָׁנָה֙ וָמַ֔עְלָה כׇּל־יֹצֵ֥א צָבָ֖א בְּיִשְׂרָאֵ֑ל תִּפְקְד֥וּ אֹתָ֛ם לְצִבְאֹתָ֖ם אַתָּ֥ה וְאַהֲרֹֽן׃ (ד) וְאִתְּכֶ֣ם יִהְי֔וּ אִ֥ישׁ אִ֖ישׁ לַמַּטֶּ֑ה אִ֛ישׁ רֹ֥אשׁ לְבֵית־אֲבֹתָ֖יו הֽוּא׃
(1) On the first day of the second month, in the second year following the exodus from the land of Egypt, יהוה spoke to Moses in the wilderness of Sinai, in the Tent of Meeting, saying: (2) Take a census of the whole Israelite company [of fighters] by the clans of its ancestral houses, listing the names, every male, head by head. (3) You and Aaron shall record them by their groups, from the age of twenty years up, all those in Israel who are able to bear arms. (4) Associated with you shall be a participant from each tribe, each one the head of his ancestral house.
(7) "And God spoke to Moses in the Sinai Wilderness" (Numbers 1:1). Why the Sinai Wilderness? From here the sages taught that the Torah was given through three things: fire, water, and wilderness.... And why was the Torah given through these three things? Just as [fire, water, and wilderness] are free to all the inhabitants of the world, so too are the words of Torah free to them....
...Another explanation: "And God spoke to Moses in the Sinai Wilderness" — Anyone who does not make themselves ownerless, hefker, like the wilderness cannot acquire the wisdom and the Torah. Therefore it says, "the Sinai Wilderness."
(R. Menahem Mendel of Vitebsk)
The Torah only stands firm in one who makes himself like a midbar hefker before those who are poor of mind and rich of mind, and he doesn’t think of himself as better than his friend. On the contrary, he should be completely nullified before his friend, and it is through this that they become united and bound up one with the other.
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)
(quoted in Itturei Torah [Hebrew], vol. 5, by Aharon Yaakov Greenberg [Tel Aviv: Yavneh, 1996], p. 9). Source: Jeffrey W. Goldwasser, "Becoming a Wilderness"
Rabbi D. Shoham, in Itturei Torah
Another reason that the Torah portion of Bamidbar is always read right before Shavuot, the time of the giving of Torah: to teach you that if you want to merit receiving Torah, you must make yourself like the wilderness, to have a great measure of humility and to feel no reason for pride, to know that you are bare and lacking all, like the wilderness.
Source: https://www.jewishrecon.org/sites/default/files/resources/document/bamidbar-wilderness.pdf