Mark 9:23 “What do you mean, ‘If I can’?” Jesus asked. “Anything is possible if a person believes.” Ministers of the Word have power to do things but lack the necessary faith to release the power that is needed to deliver those who are afflicted.
The disciples were doing deliverance but when confronted with a boy who was confronted with the evil spirit, they could not deliver him. Jesus attributed this to their lack of faith. Mark 9:17-18 One of the men in the crowd spoke up and said, “Teacher, I brought my son so you could heal him. He is possessed by an evil spirit that won’t let him talk. And whenever this spirit seizes him, it throws him violently to the ground. Then he foams at the mouth and grinds his teeth and becomes rigid. So I asked your disciples to cast out the evil spirit, but they couldn’t do it.”