Mahabharata 3.148.21

आत्मयोगसमायुक्तो धर्मोऽयं कृतलक्षणःकृते युगे चतुष्पादश्चातुर्वर्ण्यस्य शाश्वतः

ātmayogasamāyukto dharmo'yaṃ kṛtalakṣaṇaḥkṛte yuge catuṣpādaścāturvarṇyasya śāśvataḥ

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