History of the Peloponnesian War

Here, at least, let your procrastination end. For the present, assist your allies and Potidaea in particular, as you promised, by a speedy invasion of Attica, and do not sacrifice friends and kindred to their bitterest enemies, and drive the rest of us in despair to some other alliance.

Such a step would not be condemned either by the gods who received our oaths, or by the men who witnessed them. The breach of a treaty cannot be laid to the people whom desertion compels to seek new relations, but to the power that fails to assist its confederate.