Rav Yaakov of Maglanitza zy”a (Sefer Emes L’Yaakov) explains the word “bamidbor” to be a reference to “dibur” (speech). Accordingly, the pasuk is saying that one must use his speech for all areas of avodas Hashem, not merely his thoughts. The word “sinai” indicates that the proof to this is from Har Sinai, about which it is said that Hashem “spoke” (Shemos 20:1). We see that Hashem gave us the Aseres Hadibros with speech to teach us that speech is necessary for avodas Hashem.
The pasuk continues to tell us how one should start serving Hashem. The word “ohel” can mean an “ohel arai” (temporary structure). Thus, the pasuk is saying that if one’s avodas Hashem starts in a temporary manner, meaning that it is not very strong or consistent, it will lead to serving Him in a vibrant, continual way. It will become a “moed”, meaning it will be a permanent structure. The important thing is that one should start with “echad” – the first time – and then continue to “l’chodesh” – a “hischadshus”, renewal, of avodas Hashem. One can then move on to “hasheini”, serving Hashem in a second, continuous manner. It will then be “b’shana”, repeated again and again, leading to “hasheinis”, additional renewals and continuations, through which one rises from level to level.
וַיְדַבֵּר ה' אֶל מֹשֶ ׁה בְ ּמִ דְ בַּר סִ ינַי בְ ּאֹהֶל מוֹעֵד בְ ּאֶחָד לַחֹדֶשׁ הַשֵ ּׁנִי בַּשָ ּׁנָה הַשֵ ּׁנִית לְצֵאתָם וגו' מִ צְרַ יִם לֵאמֹר (א, א)
And Hashem spoke to Moshe in the Sinai desert in the Ohel Moed on the first of the second month in the second year from leaving the land of Egypt saying. (1:1)
