Rav Yechezkel Levenstein, the Mashgiach of the Ponovitch Yeshiva was a tremendous believer in Hashem. He has an entire sefer on the topic [אור יחזקאל - אמונה]. He LIVED his Emunah. צדיק באמונתו יחיה. A Tzadik lives with his Emunah.
He said "I have been working on Emunah for 40 years. If I skip a day [of working on it], everything is forgotten."
