Luke 9

Luke9:49 Now John answered and said, “Master, we saw someone casting out demons in Your name, and we forbade him because he does not follow with us.”
Luke9:50 But Jesus said to him, “Do not forbid him, for he who is not against us^[c] is on our^[d] side.”

When I read the verse, that "someone casting out demons in Your [Jesus] name" I thought of a quite interesting and funny story/event recorded in the book of acts:

Acts19:13 Then some of the itinerant Jewish exorcists took it upon themselves to call the name of the Lord Jesus over those who had evil spirits, saying, “We^[a] exorcise you by the Jesus whom Paul preaches.” (They used the name of Jesus, to cast out demons... they were playing with a power that they themselves didn't know very well..."whom Paul preaches" =>they don't really know Jesus but take him as a weapon or tool to cast out demons)
Acts19:14 Also there were seven sons of Sceva, a Jewish chief priest, who did so. (Sons of a Jewish chief priest... sons with quite some authority and reputation)
Acts19:15 And the evil spirit answered and said, “Jesus I know, and Paul I know; but who are you?” (Again we see: the evil spirits know Jesus very well (I think I have shared this already before), and the evil spirits also know the workers of God=> and they fear them. But people they don't know, they actually do not fear them, because they are under their rule (=the world is their kingdom))
Acts19:16 Then the man in whom the evil spirit was leaped on them, overpowered^[b] them, and prevailed against them,^[c] so that they fled out of that house naked and wounded. (If I am honest... when I read this verse I had to laugh and maybe I felt quite content or happy... those people who wanted to abuse the name of Jesus were finally beaten by the evil spirit. Not even God had to punish them or to do anything to them. It was the evil spirit they went to. God easily just did nothing and let the things go their own way. )
Acts19:17 This became known both to all Jews and Greeks dwelling in Ephesus; and fear fell on them all, and the name of the Lord Jesus was magnified.(So this event had great impact on the faith of the people. Afterwards they also burned their magic books (verse19) , which they could have sold for a lot of money...)

So.. just an interesting story about "casting out demons in the name of Jesus".