Mahabharata 3.198.60

गुरुशुश्रूषणं सत्यमक्रोधो दानमेव चएतच्चतुष्टयं ब्रह्मञ्शिष्टाचारेषु नित्यदा

guruśuśrūṣaṇaṃ satyamakrodho dānameva caetaccatuṣṭayaṃ brahmañśiṣṭācāreṣu nityadā

Our plain-language meaning of this verse is waiting for scholar review.