'Have Faith' in the Bible

And Jesus said to them, Because of your unbelief. For truly I say to you, if ye have faith as a grain of a mustard plant, ye will say to this mountain, Remove from here to there, and it will depart, and nothing will be impossible t

And having answered, Jesus said to them, Truly I say to you, if ye have faith, and doubt not, ye will not only do that of the fig tree, but even if ye may say to this mountain, Be thou taken up and cast into the sea, it will happen