Jesus can expel a demonic force by his word because of who he is. But in this narrative, Mark’s interest isn’t primarily in the demonic opposition, but rather in the obstacle of human disbelief. This story is foremost about faith (or belief). Faith is not a human ability that makes things possible. Rather it is risking even the little faith we have on the strength of who Jesus is. Prayer is directed faith, faith directed to the one who uniquely is able.