Musar על ברכות 66:24

That is, this true fear which our sages said of it: "The Holy One, blessed be He, has nothing in His world except a treasury of fear of heaven" (Berachot 33b). Only for Moshe was it easy to attain due to his great clinging to G-d, blessed be He. But to other people, certainly the physical is a powerful impediment within them. However it is proper for every Chasid to exert himself to attain of it all that he is capable, and it is written: "Fear the L-rd, His holy ones" (Tehilim 34:10).