Since, therefore, we have said, that the worthy man is perfected through three things, viz. through customs, laws, and disciplines, it is requisite to consider how customs or manners are usually corrupted, and how they become permanent. We shall find, then, that customs are corrupted in two ways: for they are either corrupted through ourselves or through foreigners. And through ourselves, indeed, either through our flying from pain, or through our pursuit of pleasure. For in consequence of flying from pain, we do not endure labour; and through our pursuit of pleasure, we reject what is good. Labours, however, procure good for mankind; but pleasures evil. Hence men through pleasures, becoming incontinent and remiss, are rendered effeminate in their souls, and more profuse in their expenses. But customs and manners are corrupted through foreigners, when a multitude of these dwelling with us, rejoice in the success of their emporetic employment; or when those who dwell in the suburbs, being lovers of pleasure and luxury, impart their manners to the neighbouring inhabitants. On this account it is necessary that the legislators, and prefects of the mass of the people, should diligently observe whether the customs of the city are carefully preserved, and proceed equally through all the citizens. And farther still, they should observe whether the genuine and indigenous multitude, of which the polity consists, remains pure and unmingled with any other nation; and whether the magnitude of possessions remains in the same state, and does not become excessive. For the possession of superfluities is accompanied by the desire of still more of the superfluous. After this manner, therefore, customs ought to be rendered secure.