Mahabharata 12.62.2
भीष्म उवाच · bhīṣma uvāca
ब्राह्मणस्येह चत्वार आश्रमा विहिताः प्रभोवर्णास्ताननुवर्तन्ते त्रयो भरतसत्तम
brāhmaṇasyeha catvāra āśramā vihitāḥ prabhovarṇāstānanuvartante trayo bharatasattama
Our plain-language meaning of this verse is waiting for scholar review.
Open in the book