'Unclean Spirit' in the Bible

All were amazed, and began to ask one another, saying. "What is this word? For with authority and power he commands the unclean spirits and they come out."

Those who were tormented by unclean spirits were healed also.

For Jesus was already commanding the unclean spirit to come out of the man. For many times it had seized him and held him, and they again and again kept him under guard, and put him in chains and fetters. But he would break his bonds asunder, as he was driven by the demon in to the desert.

But while he was yet coming the demon dashed him down, and cruelly convulsed him. Then Jesus rebuked the unclean spirit, and cured the boy, and gave him back to his father.