'Unclean Spirits' in the Bible

And all were amazed, so that they questioned one another, saying: What means this? What new teaching is this, that with authority he commands even the unclean spirits, and they obey him?

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

And Jesus immediately gave them leave. And the unclean spirits came out and entered into the swine; and the herd (they were about two thousand,) rushed down a steep place into the sea, and were strangled in the sea.

And he called to him the twelve, and began to send them out, two and two, and gave them authority over unclean spirits.