And thus with Yehoshafat (II Chronicles 20:20) "And they rose early in the morning and they went to the desert of Tekoa. And as they went forth Yehoshafat arose and said: 'Hear me, Judah and dwellers of Jerusalem: Believe in the L–rd your G–d and you will rest assured. Believe in His prophets and you will succeed.'" And it is written (Jeremiah 5:3) "O L–rd, are Your eyes not (looking) for belief?" (Habakkuk 2:4) "And the tzaddik in his belief shall live", and (Eichah 3:23) "They (Your mercies) are renewed every morning — Great is Your faithfulness."
The Prophet Habakkuk Distills the Entire Torah into a Single Principle
Mekhilta Tractate Vayehi Beshalach 7:27