History of the Peloponnesian War

For of the gods we hold as a matter of opinion, and of men we know as a certainty, that, in obedience to an irresistible instinct, they always maintain dominion, wherever they are the stronger. And we neither enacted this law, nor were the first to carry it out when enacted; but having received it when already in force, and being about to leave it after us to be in force for ever, we only avail ourselves of it; knowing that both you and others, if raised to the same power, would do the same.

And so, with regard to the gods, we are with good reason fearless of defeat. But with regard to your opinion respecting the Lacedaemonians, according to which you trust, that from a sense of shame, forsooth, they will assist you; though we bless your simplicity, we do not admire your folly.