“…On that side of the Jordan, in the land of Moav, Moshe began explaining this teaching, saying…” Devarim 1:5

בְּעֵבֶר הַיַּרְדֵּן בְּאֶרֶץ מוֹאָב הוֹאִיל משֶׁה בֵּאֵר אֶת הַתּוֹרָה הַזֹּאת לֵאמֹר – דברים א, ה

Before his passing, Moshe began to prepare Bnei Yisrael for their entry into the Land of Israel by recounting all that they had experienced during their forty years in the desert. The Torah adds that, as part of this address, Moshe “explained this teaching.” Rashi interprets this to mean that he taught Bnei Yisrael the Torah in seventy languages.

For what purpose did Moshe translate the Torah into seventy languages at this point? Such a project would have perhaps been relevant during Bnei Yisrael’s wandering in the desert, when their primary occupation was the study of the Torah. But Bnei Yisrael were about to begin their conquest of the Land of Israel, a process that would involve seven years of battles and another seven years that would be dedicated to dividing and settling the Land. Why was it necessary for Moshe to translate the Torah specifically as Bnei Yisrael prepared to enter this phase?

The answer is that by translating the Torah Moshe was carrying out a crucial component of Bnei Yisrael’s conquest of the seven nations who occupied the Land of Israel. For everything in the physical world has a spiritual source, and change that takes place on the physical plane must first be executed in a spiritual sense. Moshe’s translation of the Torah, breaching the language barrier between the Torah and the seventy nations, was a spiritual victory for the Torah over any opposition it faced from the nations of the world. According to the Kabbala, the seven nations who occupied the Land of Israel are the spiritual source and representation of the seventy original nations of humanity. Therefore, only once Moshe achieved a spiritual victory over all the nations, could Bnei Yisrael deliver a physical victory over them as well.

—Sichos Kodesh 5730, vol. 1, p. 358-359