The blasphemy of the Scribes having been detailed, our Lord shews that what they said was impossible, confirming His proof by an example.
Wherefore it says, “And having called them together unto Him, He said unto them in parables, How can Satan cast out Satan?” As if He had said, A kingdom divided against itself by civil war must be desolated, which is exemplified both in a house and in a city. Wherefore also if Satan’s kingdom by divided against itself, so that Satan expels Satan from men, the desolation of the kingdom of the devils is at hand.
But their kingdom consists in keeping men under their dominion. If therefore they are driven away from men, it amounts to nothing less than the dissolution of their kingdom. But if they still hold their power over men, it is manifest that the kingdom of evil is still standing, and Satan is not divided against himself.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).
Also cites: Vict. Ant. e Cat. in Marc.