Mark 9:38 "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." 39 "Do not stop him," Jesus said. "No one who does a miracle in my name can in the next moment say anything bad about me, 40 for whoever is not against us is for us. 41 Truly I tell you, anyone who gives you a cup of water in my name because you belong to the Messiah will certainly be rewarded.
Thoughts: whoever is not against us is for us. Good was being done- people were being helped because of the name of Jesus. This, even though those who used the name did not believe. One of the points of Jesus here is that God can be glorified even if evangelism does not take place. Salvation is not the only way to glorify God- though surely it is an important part. Those who give a cup of cold water, or who heal someone even if they don't believe.
Prayer: Help me to be gracious to those who do good work, Lord, even if their theology is not right. Help me to be gracious and tender and merciful.