We may have a watered-down perception of lions nowadays due to various Disney productions, but the reality is that lions are frightening creatures. The cause of this feeling of insecurity is chiefly the man-eating lion and no other animal of the forest inspires such terror into the black man's heart. In villages far in the heart of the pori, where the white man is never seen, not hundreds but thousands of Africans are annually eaten by these monsters. Nobody ever wants to actually meet a lion mono et mono. They are extremely large, they have paws the size of meat cleavers, and their cavernous mouths are armed with razor sharp teeth.
Lions are plain scary.
So is God. God is strong. Really, very, very powerful, more than we can possibly imagine and then some. At the very least, we should fear the punishment that will reach us for our evil deeds. A higher level is to tremble in awe at the thought of our standing before Him.