Fear is just another word for worship or adoration. “The fear of the Lord is the beginning of wisdom” (Prov. 9:10). It’s having a reverence of God.
As R.C. would say, the greatest need of any human being, believer or unbeliever, is to know God. Until you know the fullness of God, you don’t know what it means to fear God fully. The ability to fear God correlates to how much you know about Him. The more you have imbibed the wisdom and revelation of God’s character found in Holy Scripture, the more glorious He becomes to you. The more you see His beauty, the more you will have awe and fear and worship Him.