'Doubts' in the Bible

And he said to them, "Why are you frightened? And for what [reason] do doubts arise in your hearts?

But the one who doubts is condemned if he eats, because he does not [do so] from faith, and everything that [is] not from faith is sin.

But let him ask for [it] in faith, without any doubting, for the one who doubts is like the surf of the sea, driven by the wind and tossed about.