“Teacher,” said John, “we saw someone driving out demons in your name and we told him to stop, because he was not one of us.”
“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.Truly I tell you, anyone who gives you a cup of water in my name because you belong to the Messiah will certainly not lose their reward. (Mark 9:38-41 NIV)
If someone is effectively operating in the authority and power of the name of Christ Jesus whereby God is glorified, they are not against Christ but for Christ. And just because they are not a part of your particular circle doesn’t mean that they are not a part of God’s. So leave them alone.
“Do not touch my anointed ones;
do my prophets no harm.”