This ignorance caused the Athenians and Spartans to fight each other. The Thebans fought both of them. The Persian king fought against Greece. The Macedonians fought both sides. The Romans fought the Getae. Even earlier, the Trojan War happened for the same reasons. Alexander was Menelaus's guest. If you had seen how friendly they were, you wouldn't have believed anyone who said they weren't true friends. But then a piece of meat was thrown between them — like between dogs. That meat was a beautiful woman. War broke out over her. Now when you see brothers who seem to be friends and appear united, don't draw any conclusions about their friendship. Don't trust them even if they swear oaths and say nothing could ever separate them. You can't trust the mind of a bad person. It's unstable. It has no reliable principles to guide it. Different temptations overpower it at different times.
It was through this ignorance that the Athenians and the Lacedaemonians quarrelled, and the Thebans with both; and the great king quarrelled with Hellas, and the Macedonians with both: and the Romans with the Getae. And still earlier the Trojan war happened for these reasons. Alexander was the guest of Menelaus, and if any man had seen their friendly disposition, he would not have believed any one who said that they were not friends. But there was cast between them (as between dogs) a bit of meat, a handsome woman, and about her war arose. And now when you see brothers to be friends appearing to have one mind, do not conclude from this anything about their friendship, not even if they swear it and say that it is impossible for them to be separated from one another. For the ruling principle of a bad man cannot be trusted; it is insecure, has no certain rule by which it is directed, and is overpowered at different times by different appearances.