Prayer, in many ways, is the supreme expression of our faith in God and our faith and confidence in the promises of God. There is nothing that a man ever does which so proclaims his faith as when he gets down on his knees and looks to God and talks to God. It is a tremendous confession of faith. I mean by this that he is not just running with his requests and petitions, but if he really waits upon God, if he really looks to God, he is there saying, ‘Yes, I believe it all, I believe that you are a rewarder of them that diligently seek you, I believe you are the Creator of all things and all things are in your hands. I know there is nothing outside of your control. I come to you because you are in all this and I find peace and rest and quiet in your holy presence and I am praying to you because you are what you are.’ That is the whole approach to prayer that you find in the teaching of Scripture.
The Assurance of Our Salvation (Wheaton, IL; Crossway Books; 2000) p. 35