When an unclean spirit is gone out of a man, he walks through dry places, seeking rest, and finds none.
The unclean spirit (to himself): I will return to my house from which I came out.
When the unclean spirit returns to his house, he finds it swept and garnished.
Then the unclean spirit goes and takes with him seven other spirits more wicked than himself, and they enter in and dwell there. And the last state of that man is worse than the first.
Also found in Matthew 12:43-45