“Do not stop him,” Jesus said. “For no one who does a miracle in my name can in the next moment say anything bad about me, for whoever is not against us is for us. Mark 9:39-40 NIV
Exclusivity. Was that which John was considering, that only those who traveled with the Lord should use His name to perform miracles? Far from truth be this. One who performs a mighty work in the name of Christ, by its being accomplished reveals the presence of Christ with such a one. Such a person would not be caught then turning against the Lord. The body of Christ is meant to grow and be unified. Encourage others to do works in the name of Jesus Christ. Do not be a hinderance to them.