The following piece by Phillips Brooks gives insight into what it means to fear God in a way which I think is as close to the truth as anything I've read.
“The secret of the Lord is with them that fear him.’ Ps. 25:14
Every living thing which is really worth the knowing has a secret in it which can be known only by a few. The forms and methods of things lie open to whoever chooses to study them, but the essential lives of things are hidden away where some special sympathy or concern must find them. We can all tell how true this is with people. A careful study of the outside of a man will tell you many things but all such shrewd and careful watching will not tell you those things which we all hold back, reserved for only a few. We are deeper than our actions reveal. For example, we know the outside of a hundred houses in town, but only our own house and two or three others do we know the inner chambers and private rooms.
The greater the person is the more open and honest he will appear on the outside and the more secret is the secret of his life. Now whether we can discover the secret of life in others or not, we are aware of our own. We all know how little other people know about us. Others do not know the mainspring and the master motives that make us who we are; our purpose, spirit and intentions as well as our past experiences not many know, and we fully open our hearts to only a few.
What is necessary before one will let another read their secrets, their motives, or shall we sum it up and say the genius or our lives? It is not mere curiosity; we know how that shuts up the nature which it tries to read. Not mere awkward good-will, that too crushes the flower which it tries to examine. What is it? I think the first and foremost of them all is respect. We will not share the real secrets of our lives, the spring and power of our living to anyone who does not respect us.
No friendship, no kindliness can make you show it to them unless they truly see us as a serious, almost sacred thing. You must think there is something deep in nature or you will find nothing there. You must have an awe of the mystery and sacredness in your fellow-man or his mystery and sacredness will escape you.
Now this sense of mystery and sacredness is what we gather into that word fear referred to in the text.
It is that feeling with which you step across the threshold of a great deserted temple or into some vast dark mysterious cavern. It is not terror: that would make you turn and run away. Terror is a blinding and deafening emotion. Terror shuts up our ability to know and understand. You do not get at the secret of anything which frightens you, but fear, as we use it now, is quite a different emotion. It is a large, deep sense of the majesty and importance of anything, a reverence and respect for it. Without that no man can understand another, much less God.
As we approach God with a deep sense of His majesty, His mystery, His awesome power, we will see His secrets. It sees the love, which is behind every commandment, and His one purpose, which He has concerning us: to draw us towards and shape us into His likeness. The making of man like Himself by the power of love, that, in one word, is the purpose of God, which is the secret of the Lord!