RSV ~ Mark 9 v38 - 41

38 John said to him, “Teacher, we saw a man casting out demons in your name, and we forbade him, because he was not following us.”

39 But Jesus said, “Do not forbid him; for no one who does a mighty work in my name will be able soon after to speak evil of me.

40 For he that is not against us is for us.

41 For truly, I say to you, whoever gives you a cup of water to drink because you bear the name of Christ, will by no means lose his reward.