This is a class based on a letter of the Rebbe, Rabbi Menachem Mendel Schneerson, of the year 1954, where the Rebbe explains the mystical view of Judaism (Kabbalah) regarding the soul of non-Jews. The source quoted by the Rebbe is learned also (Zohar, Part 2, page 95b).
https://www.sefaria.org/Zohar%2C_Mishpatim.3.26?lang=he