"Jesus said unto him, If thou canst believe, all things are possible to him that believeth." Mark 9:23
Please read this to the end.
In this particular case Jesus was speaking to the father of a son who could not speak and who also was tormented severely by an evil spirit ever since he was a child. Jesus is the healer and don't forget it. The man brought his son to Jesus because he heard of what Jesus was doing. The man always wanted the son to be healed. What Jesus did and what Jesus is trying to say to this father isn't about the healing about rebuking the fowl spirit or about giving the man what he was requesting. What Jesus was trying to show the man is that belief in Jesus opens up the possibility for a supernatural, heavenly touch in a fallen natural world. That's what Jesus is trying to tell you also. "All things are possible to him that believeth."
But you need to know that not everything you believe for will come to pass. Don't be fooled by those who claim that it is your lack of faith that is keeping certain things from coming to pass. It can be, but it is not necessarily true.
It is a biblical fact that not everyone receives everything they pray for.
It is a biblical fact that not everyone is healed, (while on earth).
It is a biblical fact that not everyone gets rich.
It is a biblical fact that not everyone's child comes to the Lord.
It is a biblical fact that not everyone gets to grow old.
There are entire ministries trying to get you to believe in and for things that are not even in the plan of God for your life. You need to pray to God and listen attentively about the situation. What God might do or allow might not be what you think. However, with the mind of Christ, and the guidance of the Holy Spirit you will also not be left in a lurch wondering if God is even there.
Use your faith to trust God despite the circumstances or outcomes of events in your life. Not all of them are because you did this or that or because your faith is less than perfect. Some events fit into the global will of God and the outcome of your situation is part of the bigger picture. But also know that:
God does answer prayers
God does heal
God does assist people to acquire wealth
God does bring children to the Lord
God does allow many people to grow old
What God does in your situation should be what you truly desire. It's true. Instead of trying to get God to bless what you want, try finding out what God has prepared for you and start desiring that. Try praying for the things you hear God talking to you about. Try praying for the people that God puts in your path. Try praying for the people who have hurt you, used you or defrauded you. It is the will of God for your life. Try finding out from scripture what is the acceptable will of God for your life. Try laying down the things you know are harming you or that you already know are against the express will of God. "All things are possible to him that believeth." But not all things that you believe for are necessarily possible or in the will of God. Can you see the difference?