The 613 Mitzvos on One Foundation
Emunah & bitachonTorah learning
The Gemara teaches that Moshe was given 613 mitzvos, and that Chavakuk came and established all of them upon one foundation, in the words "But the righteous person shall live by his faith." In this pasuk the whole Torah rests on emunah, the steady faith through which a tzaddik lives.
Source: Makkos 23b-24a (on Chavakuk 2:4)