'Unclean Spirits' in the Bible

And they were all amazed, so as to question among themselves, saying, What is this? What is this new doctrine, that he commands with authority, and the unclean spirits also obey him?

And the unclean spirits, whenever they saw him, fell down before him, and cried out, saying, Thou are the Son of God.

And straightaway, Jesus allowed them. And the unclean spirits having come out, entered into the swine. And the herd stampeded down the slope into the sea, and were drowned in the sea. And there were about two thousand.

And he summons the twelve, and began to send them forth in pairs. And he gave them authority over the unclean spirits.