The nature of man is to be fearful of everything- fearful of the unknown, of crime, of competition, of sickness, of pain, of death, etc.
If man is so prone to fear, why is he not as instinctively afraid of the Almighty, the most powerful force on earth?
Hashem removed man’s ability to intuitively perceive His magnitude in order to give him His greatest gift of bechira chofshit, free choice.
Consequently, man must actively seek out and pursue knowledge of the Divine. That is the only way to acquire the appropriate amount of fear in order to be motivated to choose good over evil.
King David says:
“If you seek it as you do silver and search for it as for treasures, then you will understand the fear of Hashem and attain knowledge of God.” (Proverbs 2: 4-5)
(Adapted from A Letter for the Ages, pages 54-55)