What does the Bible say about doubt and faith?

“Now faith is assurance of things hoped for, proof of things not seen.”

“Immediately the father of the child cried out with tears, “I believe. Help my unbelief!””

“But if any of you lacks wisdom, let him ask of God, who gives to all liberally and without reproach, and it will be given to him. But let him ask in faith, without any doubting, for he who doubts is like a wave of the sea, driven by the wind and tossed.”

“So faith comes by hearing, and hearing by the word of God.”

“On some have compassion, making a distinction,”

“Immediately Jesus stretched out his hand, took hold of him, and said to him, “You of little faith, why did you doubt?””

“Then he said to Thomas, “Reach here your finger, and see my hands. Reach here your hand, and put it into my side. Don’t be unbelieving, but believing.” Thomas answered him, “My Lord and my God!” Jesus said to him, “Because you have seen me, you have believed. Blessed are those who have not seen and have believed.””

“Trust in the LORD with all your heart, and don’t lean on your own understanding. In all your ways acknowledge him, and he will make your paths straight.”