My first thought is: If someone doubts the Word of God, and IF they read the Word of God,
they are not applying what it says to their own life. The bible clearly says the following:
"Immediately, Jesus reached out, caught hold of him, and said, “You have so little faith! Why did you doubt?”
Matthew 14:31 (GW)
"Jesus answered them, “I can guarantee this truth: If you have faith and do not doubt, you will be able to do what I did to the fig tree. You could also say to this mountain, ‘Be uprooted and thrown into the sea,' and it will happen."
Matthew 21:21 (GW)