I generally don't like it when someone just posts a scripture without any comment, and assumes that anyone with any common sense or intelligence at all will interpret it the same way he does. But right now, I'm going to do just that...
Mark 9:38-40 And John answered him, saying, Master, we saw one casting out devils in thy name, and he followeth not us: and we forbad him, because he followeth not us. 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. For he that is not against us is on our part.
Luke 9:49-50 And John answered and said, Master, we saw one casting out devils in thy name; and we forbad him, because he followeth not with us. And Jesus said unto him, Forbid him not: for he that is not against us is for us.