I've often heard people quote the verse in James that says to not doubt when you pray, "when you ask, you must believe and not doubt, .... That person should not expect to receive anything from the Lord" (1:6, 7). I've been taught that this means that when you pray for something and don't get it, it's because you're doubting.
I've got a problem with that interpretation because I don't think it takes into account: "Lord, I believe. Help my unbelief!" (Mark 9:24) That's what the man whose son was possessed by a demon said after the disciples couldn't help him. He told Jesus what the problem was then begged, "Help him if you can." Jesus said, "'If you can'? Everything is possible for one who believes' (v. 23). That's when the man made the above statement.
Did Jesus say, "Hey, dude, if you're going to be doubting, you can't expect to receive anything from me! Forget it. Come back when you're not double-minded"? No! He healed the man's son without further ado.
So what was Jesus' problem? Didn't he know that the man wasn't supposed to expect something of the Lord if he was doubting? Was that a secret from him? Did it take James to discover it?
No, not at all! The "secret" has been withheld from those who preach James that way. The problem is in taking things out of context.
When James said don't doubt when you pray, he had a specific prayer in mind! Yes he did. He wasn't talking about prayer in general. Instead he said "If any of you lacks wisdom, you should ask God, who gives generously to all without finding fault, and it will be given to you" (1:5). That's the prayer that you must not doubt!
When you think about it, James' statement is only logical, isn't it? Can God respond favorably to: "Uh, I wanna get wisdom God, if ya think ya don' mind givin' it ta me? Maybe. If ya think I kin use it right-like"?
Truthfully, "Such a person is double-minded and unstable in all they do" (James 1:8). God can't give that person wisdom because they don't have the state of mind to receive it!
James uses the "double-minded" kind of idea a lot - hearing and not doing, faith without deeds, blessings and curses coming out of the same mouth, lacking good things because you want them for selfish reasons.
He also tells us what this wisdom is that we need to ask for without doubting that we'll get it: "But the wisdom that comes from heaven is first of all pure; then peace-loving, considerate, submissive, full of mercy and good fruit, impartial and sincere. Peacemakers who sow in peace reap a harvest of righteousness" (3:17-18).
If you want that kind of wisdom, ask for it without doubting. For all other prayer requests, feel free to ask with a "Lord I believe, help my unbelief!"