Doubt: Fear - Suspect -  Distrust to call into question the truth of - to be uncertain. John 20:24-25 Doubting Thomas had a problem with beliebving because he wasn't there with the rest when they saw Jesus after he rose from the grace. 

Many times because we were not there when the pastor preached on faith, when I was delivered, when God demonstrated a situation to me. We simply don't believe. The first and main Key with coming to God and staying with God is to BELIEVE. The word faith means complete trust or comfident in someone or something. Trust belief is a act of faith. Without believing in God or that there is a God you want find him. Once you activate a grain of faith that he is you will begin to find.