Assuming we are going by the standard definition of faith (believing in spite of or in absence of evidence) a being that ran on pure faith would be completely shut out from all outside stimuli, or at least incredibly proficient at ignoring them. One could argue that to a specimen such as this, all it would take for said subject to move a mountain in their view of reality would be to believe they could move a mountain. This would not mean that the mountain actually moved in the real world; just that they've trained themselves to hallucinate very well.
Are you proposing that Jesus (assuming existence, reliability of that quote, etc.) was simply insane?