The Bible says the prayers of those who think God cannot help or will not are useless
 
The Bible at James 1 says the man who doubts cannot expect to receive anything from the Lord for he is devious and erratic. In other words, he is trying to trick God. If the doubter can’t expect an answer for prayer the sinner can expect less. Praying then is blowing your own trumpet. It is saying you don’t doubt and/or that you don’t sin. It’s only for hypocrites.
 
The Bible sees doubt as more than just mistrusting God in your head. Faith is seen as belief in action which means that each sin can in its own way be called a doubt.
 
Jesus famously said, contradicting James, that prayer can move a mountain from where it is and transplant it into the sea if you have a little faith, that is faith as big as a mustard seed. Some believers say he didn't mean weak faith but the unshakeable faith of one that barely knows anything about God. The faith is small, a mustard seed, in content but strong in force. Can you really have faith in something you hardly know? It would be better faith than that of a person who does know God but who has weak faith!
 
So Jesus taught the absolute necessity of faith for getting prayers answered. “What things soever ye desire, when ye pray, believe that ye receive them, and ye shall have them” – Jesus, Mark 11:24 King James Bible.
 
Many people with very weak faith and who are full of doubts report cures at the hands of healers. I am not saying the cures have anything to do with God. What I am saying is that it is bigotry to say that prayers are answered according to faith for, if there is a God, who knows? So James that is you told! Your saying that is just as much a boast about yourself as it is for you to say that Jesus is the only way to God like your Christian brethren do for that is saying, “I’m great and better than you Buddhists and other pagans for I know something you don’t – how to pray and prayer is the only way to Heaven”. Jesus said he was the way and the truth and the life and no man could come to God except by him (John 14:6) so his prayers did not gain him much genuine virtue either. Prayers and sacraments just give false hope.
 
Jesus suspected that prayer was hypocrisy and useless when he said sincere people go out of their way to do it in private. You cannot tell how well prayer is answered if people hide their prayer life from you. Jesus was trying to prevent people from seeing the futility of prayer. His knowledge of this uselessness still didn’t stop him deceitfully advocating prayer.
 
Jesus criticised the pagans who prayed tonnes thinking that they would be heard for their many words (Matthew 6:7). So, quality matters and quantity does not. It follows that if one person prays for the world to be holy that prayer will do and is as good as a billion billion similar prayers. Yet Christianity blames the falls of priests and religious into sin on people not praying enough for them. God would find that unspeakably offensive for it accuses him of neglecting them because other people didn’t ask him to help them. It contradicts the stuff about quality alone being what counts. (All apparitions of the Virgin Mary and the saints and Jesus make the same error.) It is blasphemous to order people to always pray like the Bible does (1 Thessalonians 5:17) for when one prayer does there is no need for any more. God would not order people to do what they don’t need to do on pain of sin and punishment if he is love. But the Church still says it's a sin not to pray daily and to go to Church regularly!
 
Jesus told the parable of the corrupt judge (Luke 18:1-8). The gospel says the parable is about the importance of not losing heart. In it the judge refuses to help a woman and doesn’t care about her. But she asks for his help many times and he gets scared and then gives her what she wants. Then Jesus says that this shows that God will help those who call out to him day and night. Christians deny it but it cannot be denied by honest people that Jesus was saying you have to ask God a lot of times to get his attention. The context proves it. Jesus then was turning God into something no better than a man. Some Son of God then! Jesus was a fraud. His miracles were not genuine for his doctrine was false.
 
All doubt so even if there is a God to given an answer to prayer, it does not follow that anybody's prayers have been answered. They only think they have.

If a doubter asks for x and x happens then the doubter is going to imagine his prayers work and thus doubters will be praying and setting innocent people up for a disappointment.  That x happened is only a coincidence even if there is a God who answers prayer for he does not entertain doubters.