History of the Peloponnesian War

For although it be in the articles that the cities written with neither of the parties may come in to whether of them they please, yet it holds not for such as do so to the detriment of either, but only for those that, having revolted from neither part, want protection and bring not a war with them instead of peace to those (if they be wise) that receive them.

For you shall not only be auxiliaries unto these but to us, instead of confederates, enemies. For if you go with them, it follows they must defend themselves not without you.

You should do most uprightly to stand out of both our ways; and if not that, then to take our parts against the Corcyraeans (for between the Corinthians and you there are articles of peace, but with the Corcyraeans you never had so much as a truce) and not to constitute a new law of receiving one another's rebels.