Mahabharata 15.8.12

एष एव परो धर्मो राजर्षीणां युधिष्ठिरसमरे वा भवेन्मृत्युर्वने वा विधिपूर्वकम्

eṣa eva paro dharmo rājarṣīṇāṃ yudhiṣṭhirasamare vā bhavenmṛtyurvane vā vidhipūrvakam

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