Moses began the Song of Ha'azinu with the words, “Listen, O heavens... Let the earth hear...” (Devarim 32:1) The prophet Isaiah also used a similar phrase, but in reverse: “Hear, O heavens, and listen, O earth.” Our Sages explain that the expression “to listen” (leha'azin) refers to something close, while “hear” (lishmo'a) refers to something distant. Moses was close to heaven, so he said, “Listen, O heavens,” while Isaiah was close to the earth, so he said, “Listen, O earth.”
The teachings of chassidut explain that “heaven” refers to the World of Atzilut (Emanation), where the sole existence is the G-dly existence, and everything is viewed through pure, Divine lenses. In contrast, “earth” refers to the worlds that are part of creation, where there is a sense of the created beings’ own self-existence.
A Soul of Atzilut
Moses was a “soul of the World of Atzilut.” Even when he was here, in this world, he was essentially at the level of the World of Atzilut. Therefore, as Maimonides explains, Moses did not need to detach from his physicality when receiving prophecy, unlike other prophets. This is because his physical body did not hinder the Divine revelation at all; on the contrary, it was a vessel for the Divine, with the Shechina (Divine Presence) speaking through his throat.
In contrast, Isaiah was like other prophets. Although he saw sublime things, the Divine revelation was not natural for him, because the limitations of creation concealed the Divine truth. Therefore, when he spoke of the heavens, he said, “Hear, O heavens,” because the World of Atzilut was distant from him.
The Ultimate Connection
Based on this, we can understand why Moses had to speak about matters of the earth, while Isaiah simultaneously spoke of the heavens. It would seem that Moses should have only spoken to the World of Atzilut, which was close to him, and Isaiah should have only spoken to the earth, which was close to him.
However, the purpose is for the World of Atzilut to illuminate and radiate downward to the worlds of created beings, while the lower worlds strive to ascend to the World of Atzilut. Moses's purpose was to bring down Divine revelations from above to below, which is why he also spoke to the earth. And Isaiah, who served as a prophet of rebuke, stirred the Children of Israel to ascend from below to above, which is why he also spoke to the heavens.
Torah and Business
In our Divine service as well, there is the aspect of “heaven” and the aspect of “earth.” Those who “dwell in the tent”, immersed in the world of Torah, are at the level of “heaven.” Business people, who dedicate their primary time to worldly matters, are in the aspect of “earth.” Each person from both groups must know that they must connect with the other level.
Those who “dwell in the tent” must remember that “anyone who says I have only Torah, doesn't even have Torah,” and they must also engage in the performance of mitzvot. Meanwhile, business people must remember that they must be connected to Torah, to study Torah every day, at least one chapter in the morning and one in the evening. The difference between them is a matter of what their primary focus is. However, it is certain that both aspects must exist within every single person.
(from the teachings of the Rebbe, Likutei Sichot Vol. 5, pg. 415)
