'Doubts' in the Bible

“Why are you troubled?” He asked them. “And why do doubts arise in your hearts?

Get up, go downstairs, and accompany them with no doubts at all, because I have sent them.”

Then the Spirit told me to accompany them with no doubts at all. These six brothers accompanied me, and we went into the man’s house.

But whoever doubts stands condemned if he eats, because his eating is not from a conviction, and everything that is not from a conviction is sin.