Luke 9:49-50 (New International Version)
49"Master," said John, "we saw a man driving out demons in your name and we tried to stop him, because he is not one of us."
50"Do not stop him," Jesus said, "for whoever is not against you is for you."
Also: Mark 9:38-40
Web definitions for sectarianism
a narrow-minded adherence to a particular sect or party or denomination; "he condemned religious sectarianism"
wordnetweb.princeton.edu/perl/webwn
Numbers 11:26-29 (New International Version)
26 However, two men, whose names were Eldad and Medad, had remained in the camp. They were listed among the elders, but did not go out to the Tent. Yet the Spirit also rested on them, and they prophesied in the camp. 27 A young man ran and told Moses, "Eldad and Medad are prophesying in the camp."
28 Joshua son of Nun, who had been Moses' aide since youth, spoke up and said, "Moses, my lord, stop them!"
29 But Moses replied, "Are you jealous for my sake? I wish that all the LORD's people were prophets and that the LORD would put his Spirit on them!