Udyoga-parva Adhyāya 34 — Vidura’s Counsel on Deliberation, Speech-Discipline, and Dharmic Kingship
सामुद्रिकं वणिजं चोरपूर्व शलाकधूर्त॑ च चिकित्सकं च | अरिं च मित्र च कुशीलवं च नैतान् साक्ष्ये त्वधिकुर्वीत सप्त,हस्तरेखा देखनेवाला, चोरी करके व्यापार करनेवाला, जुआरी, वैद्य, शत्रु, मित्र और नर्तक--इन सातोंको कभी भी गवाह न बनावे
sāmudrikaṁ vaṇijaṁ corapūrvaṁ śalākadhūrtaṁ ca cikitsakaṁ ca | ariṁ ca mitraṁ ca kuśīlavaṁ ca naitān sākṣye tv adhikurvīta sapta ||
Vidura advises that, in matters requiring testimony, one should not appoint as witnesses seven kinds of persons: a physiognomist or palm-reader, a trader with a history of theft, a gambler skilled in deceit, a physician, an enemy, a friend, and a professional performer.
विदुर उवाच
A witness must be free from strong bias and from habits or livelihoods associated with deception; therefore certain categories—enemy, friend, gambler/cheat, thief-turned-merchant, and others—should be excluded to safeguard impartial justice.
In Vidura’s counsel on dharma and governance during the Udyoga Parva, he lays down practical rules for legal procedure, specifying which kinds of people should not be accepted as witnesses in disputes.