One who contributes from his wealth for the purpose of writing or publishing a sefer of a Tzaddik –
Behold, at any given time, and in any corner of the world, that a person studies from this sefer, the Tzaddik [on high] evokes merit on behalf of the donor through whom the sefer was disseminated.
—The Rebbe, Igrot Kodesh, vol 2
By Rabbi Shmuel of Lubavitch
Delivered in 1869, this discourse revolutionizes the age-old notion of Monotheism, i.e., that there is no other god besides him. Culling from the Talmudic and Midrashic sources, the discourse makes the case that not only is there no other god besides him, there is nothing besides him-literally. The only thing that truly exists is G-d.