'Have Faith' in the Bible

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

Jesus answered and said to them, Verily I say to you, If ye have faith, and doubt not, ye shall not only do this which is done to the fig-tree, but also, if ye shall say to this mountain, Be thou removed, and be thou cast into the sea; it shall be done.