'Doubt' in the Bible

nor did he doubt God's promise out of a lack of faith. Instead, his faith became stronger and he gave glory to God,

For I am convinced [and continue to be convinced—beyond any doubt] that neither death, nor life, nor angels, nor principalities, nor things present and threatening, nor things to come, nor powers,

Do not put on one side him who is feeble in faith, and do not put him in doubt by your reasonings.

But he who is in doubt is judged if he takes food, because he does it not in faith; and whatever is not of faith is sin.