“Then this unclean spirit says.

‘I will return

To my house,

From which I came.’

When he comes,

This spirit finds it empty.

It is swept.

It is put in order.

Then the unclean spirit goes

And brings along

Seven other spirits

More evil than itself.

They enter there.

They live there.

The last state of that person

Is worse than the first.

Thus,

It will it be also

With this evil generation.”

τότε λέγει Εἰς τὸν οἶκόν μου ἐπιστρέψω ὅθεν ἐξῆλθον· καὶ ἐλθὸν εὑρίσκει σχολάζοντα καὶ σεσαρωμένον καὶ κεκοσμημένον.

τότε πορεύεται καὶ παραλαμβάνει μεθ’ ἑαυτοῦ ἑπτὰ ἕτερα πνεύματα πονηρότερα ἑαυτοῦ, καὶ εἰσελθόντα κατοικεῖ ἐκεῖ· καὶ γίνεται τὰ ἔσχατα τοῦ ἀνθρώπου ἐκείνου χείρονα τῶν πρώτων. οὕτως ἔσται καὶ τῇ γενεᾷ ταύτῃ τῇ πονηρᾷ.

This saying about the returning unclean spirit can also be found word for word in Luke, chapter 11:25-26, indicating a Q source.  This implies a failed exorcism or a failed healing, so that the evil unclean spirit would return with more evil spirits.  Thus, the final state of that person would be worse than it was in the beginning.  This unclean spirit said to itself that it would return to its house or the place or person that it had come from (τότε λέγει Εἰς τὸν οἶκόν μου ἐπιστρέψω ὅθεν ἐξῆλθον).  Nothing had been put in its place, because this unclean spirit found it empty or unoccupied (καὶ ἐλθὸν εὑρίσκει σχολάζοντα), swept clean (καὶ σεσαρωμένον) and in order, newly decorated (καὶ κεκοσμημένον).  Thus, the unclean spirit went and brought 7 more evil spirits (τότε πορεύεται καὶ παραλαμβάνει μεθ’ ἑαυτοῦ ἑπτὰ ἕτερα πνεύματα πονηρότερα ἑαυτοῦ).  All these evil spirits entered and lived there (καὶ εἰσελθόντα κατοικεῖ ἐκεῖ·).  Finally, the last state of that person would be worse than the original situation (καὶ γίνεται τὰ ἔσχατα τοῦ ἀνθρώπου ἐκείνου χείρονα τῶν πρώτων).  Thus, it would be the same for this evil generation (οὕτως ἔσται καὶ τῇ γενεᾷ ταύτῃ τῇ πονηρᾷ).  Jesus had just called this generation evil in chapter 12:19.