Mark 9:38-41 (Also found in Luke 9:49-50)
John: Master, we saw one casting out devils in your name, and he does not follow us: and we forbade him, because he does not follow us.
Jesus: Forbid him not, for there is no man which shall do a miracle in my name, that can lightly speak evil of me. For he that is not against us is on our part.
Luke 9:50 says “for he that is not against us is for us.”
Jesus (continued): For whoever gives you a cup of water to drink in my name, because you belong to Christ, he shall not lose his reward