Montesquieu

When a peo­ple has a good ethos, the laws become sim­ple. Plato says that Radamanthus, who gover­ned a highly reli­gious peo­ple, dis­pat­ched all law­suits expe­di­tiously, relying only on an oath for each case.1 But, says the same Plato, when a peo­ple is not reli­gious, an oath can be used only in those cases where the per­son swea­ring is disin­te­res­ted, like a judge and wit­nes­ses.2

Laws, book XII.

Ibid.