Once, the Previous Lubavitcher Rebbe, said the following at a Chassidic gathering:[1]
“The Alter Rebbe effectuated that chassidim should be mighty.”
True strength is as expressed in Avot (4:1) someone who conquers their evil inclination. The Alter Rebbe—through his teaching of chassidut—gave each and every one of us, the ability to be truly mighty.
[1] Sefer HaSichot, 5704, Pg. 106