At Hellenica 5.4.1, prior to his account of the recapture of the Cadmea, Xenophon writes:
one could bring up many other instances, both Greek and barbarian, which show that the gods neglect neither impious persons nor those who do wicked deeds. Now I will take up the matter at hand. The Spartans, having sworn to let the cities [of Greece] be free, seized the acropolis at Thebes; by the very people alone whom they wronged they were punished, having themselves never been defeated in battle before. As for the Thebans who brought the Spartans into the citadel and who wanted to enslave their city to the Spartans so that they might be tyrants themselves, only seven of the exiles were needed to destroy their rule. I will now explain how this happened.