'Doubting' in the Bible

The disciples therefore looked one on another, doubting of whom he spoke.

but rise up, go down, and go with them, nothing doubting, because I have sent them.

And the Spirit said to me to go with them, nothing doubting. And there went with me these six brethren also, and we entered into the house of the man,

but let him ask in faith, nothing doubting. For he that doubts is like a wave of the sea driven by the wind and tossed about;