James 1:5-6

If any of you lacks wisdom (to guide him through a decision or circumstance), he is to ask of God, who gives to everyone generously and without rebuke or blame and it will be given to him. But he must ask (for wisdom) in faith, without doubting (God’s willingness to help), for the one who doubts is like a billowing surge of the sea that is blown about and tossed the wind. 

What is the difference between a doubter and a believer? Where the focus resides and the thoughts the focus generates. Faith comes from a concentration and belief in the word of God. Doubt comes from letting the interference of the devil and the world into the mind and believing that over the Word of God.