James McConkey wrote many wonderful books on the Christian life, some of which you can find in various places on this web site. His book on prayer is also a gem. I will slowly add chapters as I am able.
"We find ourselves saying: Why cannot we cast out the demons of drink and impurity from men? Why cannot we accomplish mighty results in the sphere in which God has placed us? The answer is found in the very terms of the question — because "we" are trying to do it in our own power. We think it is our energy; our plans and efforts; our wisdom; our power that is to bring things to pass. And some day we waken up to find the power gone and the fruitfulness missing and the blessing lost from our lives, and we say as the apostle said, Why cannot we do these things? And back to us comes the same answer our Lord gave to the failure of His disciples, "Have faith in GOD." As though He said: "YOU cannot cast out devils, nor do anything else, in your own strength. It is GOD alone who can do these things. But if you will learn the secret of the prayer life and come to Him, then, though you yourselves cannot do and are never, in your own strength, meant to do, He fulfils His great promise: "If — ye — ask — I — will — do."