Rashi explains that this “voice” ceased at the boundaries of the Ohel Moed. He adds that this was not because the voice was weak, since it was an amazingly powerful sound. Hashem intercepted this sound so that it would not be heard outside of the Ohel Moed. Why did Hashem create such a powerful voice only to miraculously disrupt its emanation?
Horav Y. Neiman, z.l., offers a profound insight into this matter. This voice was not miraculously intercepted, rather, one is required to be within the confines of the Ohel Moed in order to hear the voice of Hashem. The sanctity of the Ohel Moed provided a unique atmosphere for increased spiritual growth. Consequently, only Moshe — and not all of Bnei Yisrael — was worthy of this special opportunity. Hashem’s voice exists everywhere. One must be attuned to it. The Ohel Moed symbolizes any place or any time in which one involves himself in Torah study. The holiness emanating from this lofty endeavor so thoroughly permeates one’s essence that he is transformed into another person with unique capabilities. He is able to hear the sounds of holiness and to process the Divine message of the Almighty.