There is only one cause for failure in prayer. Jesus taught that it was “Because of your unbelief.”
Some argue that this cannot be the trouble in their case, but the fact remains that this is the sole reason, providing one is a qualified son of God. Suppose we search the Scriptures for some other reason and see if it can be found. . . Suppose we become honest enough to investigate what God says and give Him the benefit of any doubt. If we would answer ourselves with the Bible, we would find a number of Scriptures that plainly prove this.