Usually, when you ask Christians today what the Bible means when it talks about fearing God, you'll hear the words respect, awe, or reverence used. Rarely do you hear anything resembling the tone Job or David uses in Job 9 or Psalm 38. David says, "There is no health in my bones because of my sin." Job says, "Who has defied Him without harm?" and then goes on to describe the awesome destructive power the Lord possesses. Both of these men seem to truly be afraid of what God can and will do. Yes, reverence, respect, and awe are part of that, but I believe people from scriptures that have encountered God were truly afraid like David and Job. Proverbs 9:10 tells us that "The fear of the Lord is the beginning of wisdom and the knowledge of the Holy One is understanding." To know God is to fear Him.
And both Job and David did know God. They seemed to have a great understanding of who He was and how He loved his children. I don't think those two things are unrelated. If we want to be people like Job or David, let's make sure we understand what it really means to fear God.