Mahabharata 13.116.19

दुष्करं हि रसज्ञेन मांसस्य परिवर्जनम्चर्तुं व्रतमिदं श्रेष्ठं सर्वप्राण्यभयप्रदम्

duṣkaraṃ hi rasajñena māṃsasya parivarjanamcartuṃ vratamidaṃ śreṣṭhaṃ sarvaprāṇyabhayapradam

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