Adler tentatively classifies the headword phrase as a proverb, but it is not in the paroemiographers; nor does the glossing material take the usual form of glosses on proverbs. Indeed as an explanation (ga/r) of the phrase 'the medism of Pausanias' it does not really work, and seems rather to be from the middle of a broader explanatory narrative.
For the episode in question, in the second quarter of the C5 BCE, which ruined the careers of a Spartan king (P.) and an Athenian war-hero (T.), see principally Thucydides 1.128-138 (web address 1).