The Rebbe explains that Pnimiyus HaTorah enhances Nigleh, just as added vitality in the soul affects the body. He advises avoiding debates with opponents, as they distract from the true mission. Regarding a question on Tanya (ch. 24), he references sources clarifying the connection between Torah, Hashem, and Bnei Yisrael.
https://www.torahrecordings.com/rebbe/igroskodesh/014/005/5151