Although the Book of Devarim is the word of G-d just as the other four books of the Torah are, we are told that Moshe transmitted it differently to Bnei Yisrael. In the first four books, “Moshe spoke on behalf of the Almighty,” but in the book of Devarim, “Moshe spoke in his own name”—“by Divine inspiration.”
This means that in the first four books, Moshe served merely as a messenger to transcribe G-d’s words and convey them to Bnei Yisrael as he received them.
Due to the Torah’s inherent transcendence of creation—the finite, mortal mind included—if G-d had transmitted all of the Torah in this manner, then anything we might ever grasp from the Torah would at best reflect the Divine truth, but inherently could not be the essential Divine wisdom, which transcends the created being.
In the Book of Devarim, however, G-d communicated His word to Moshe in a manner that Moshe could internalize, and Moshe in turn “spoke in his own name,” conveying the Divine wisdom that his mind had perceived. Thereby, the Divine wisdom of the Torah itself became graspable by the human mind.
The Book of Devarim is called Mishneh Torah—the repetition of the Torah, because it is a review of the previous four books. Since the book of Devarim has the dual quality of being the word of G-d yet “descending” into the realm of human comprehension, by extension, every other part of the Torah has this quality as well.
In addition, since Moshe’s role was to connect every member of the Jewish community with G-d, this became the reality of Torah study for every Jew. By virtue of the Book of Devarim (which “Moshe spoke in his own name,” but is still the word of G-d like the other books of the Torah), any Jew, regardless of his spiritual state or level of comprehension, by studying and comprehending any part of the Torah, can ingest the very word of G-d—its divinity neither tainted nor diminished.
—Likkutei Sichos, vol. 19, pp. 9–12
