Luke 4:33

Messiah’s appearance served notice on the demon world that He purposed to destroy their work. Consequently the demons began to oppose Jesus immediately. Jesus continued this holy war throughout His ministry, and His disciples extended it after His departure (Luke 9:1-2; Luke 10:9-10; Luke 10:17). The Gospel writers used the terms "evil" and "unclean" interchangeably to describe these demons. They were evil in their intent and they produced uncleanness in contrast to the goodness and holiness that the Holy Spirit produces in those whom He inhabits. [Note: See Zondervan Pictorial Encyclopedia of the Bible, s.v. "Demon, Demoniac, Demonology," by R. K. Harrison, 2:92-101.] Possibly Luke specified that this was an unclean demon because the Greeks thought there were good and evil demons. [Note: Theological Dictionary of the New Testament, s.v. "daimon," by W. Foerster, 2:9.]