(9:21–29) Jesus graciously accepts the imperfect faith of the boy’s father and casts out the demon from the boy. Jesus teaches his disciples that prayer is the only way to cast such a demon out. Their resistance to the message of the Christ’s suffering has weakened their prayer life and thus their spiritual power. 9:21–22 Mark explains more about the boy’s plight, which we discover has been from childhood. The demon has tried to kill the boy by casting him into fire or water.