Arthashastra
सर्व उपधा शुद्धान् मन्त्रिणः कुर्यात् ॥
Those whose character has been tested under all kinds of allurements shall be employed as prime ministers (mantrinah).
english translation
sarva upadhA zuddhAn mantriNaH kuryAt ॥
hk transliteration by Sanscript