Mark 9:35-40

35And he sat down, and called the twelve; and he saith unto them, If any man would be first, he shall be last of all, and servant of all. 36And he took a little child, and set him in the midst of them: and taking him in his arms, he said unto them, 37Whosoever shall receive one of such little children in my name, receiveth me: and whosoever receiveth me, receiveth not me, but him that sent me.

38John said unto him, Teacher, we saw one casting out demons in thy name; and we forbade him, because he followed not us. 39But Jesus said, Forbid him not: for there is no man who shall do a mighty work in my name, and be able quickly to speak evil of me. 40For he that is not against us is for us.