More than The Name of Jesus

Acts 19:13-16 
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 exorcise you by the Jesus whom Paul preaches.” 14 Also there were seven sons of Sceva, a Jewish chief priest, who did so. 15 And the evil spirit answered and said, “Jesus I know, and Paul I know; but who are you?” 16 Then the man in whom the evil spirit was leaped on them, overpowered them, and prevailed against them, so that they fled out of that house naked and wounded.

Those who attempted to command evil spirits in Jesus’ name but who did not know Jesus simply had no authority over them, so they were able to turn against them.  Just saying, “in the name of Jesus” does not work, because all authority in heaven in earth is His, and nobody else has any apart from Him.  So the evil ones legitimately ask, “who are you?”  But we who are in Christ have His power and authority to bring light in this present darkness.