Mark 9:38-40

38And John answered him saying, Teacher, we saw some one casting out demons in thy name, who does not follow us, and we forbad him, because he does not follow us.

39But Jesus said, Forbid him not; for there is no one who shall do a miracle in my name, and be able soon [after] to speak ill of me;

40for he who is not against us is for us.