'Have Faith' in the Bible

And he saith unto them, Because of your little faith: for verily I say unto you, If ye have faith as a grain of mustard seed, ye shall say unto this mountain, Remove hence to yonder place; and it shall remove; and nothing shall be impossible unto you.

And Jesus answered and said unto them, Verily I say unto you, If ye have faith, and doubt not, ye shall not only do what is done to the fig tree, but even if ye shall say unto this mountain, Be thou taken up and cast into the sea, it shall be done.

And Jesus answering saith unto them, Have faith in God.

But we are not of them that shrink back unto perdition; but of them that have faith unto the saving of the soul.