Mark 9:39 in the King James Version
But Jesus said, Forbid him not: for there is no man which shall do a miracle in my name, that can lightly speak evil of me.
Context
38 John said to him, “Teacher, we saw someone who doesn’t follow us casting out demons in your name; and we forbade him, because he doesn’t follow us.”
39 But Jesus said, “Don’t forbid him, for there is no one who will do a mighty work in my name and be able quickly to speak evil of me.
40 For whoever is not against us is on our side.