I didn't hear it that way when I read it this time. There is something a little odd in this story. In this particular story faith has no object. Now faith is the assurance of things hoped for, the conviction of things not seen. I want to ask - in what or for what purpose.
Faith has to have an object or it is nothing.
Jesus' response doesn't help matters much. He says that if they had mustard seed faith they could move a mulberry tree to jump into the sea and it would do it. I don't know what to do with that at all. I'm not sure exactly what Jesus intended, but I can tell you some of what I think about faith. I think you either have it or you don't.