people cast out demon by jesus name

John said to Jesus: "teachers, we saw someone who does not follow us cast out demon in your name and we forbade him, because he does not follow us." but Jesus said: "You shall not prevent him! because no one who has held a miracle by my name, can curse me. who is not against us is on our side. I tell you truly, whoever gives you a drink a cup of water because you are a follower of Christ, he will not lose his reward.