Mahabharata 3.82.80

ब्राह्मणेन भवेच्चीर्णं व्रतं द्वादशवार्षिकम्इतरेषां तु वर्णानां सर्वपापं प्रणश्यति

brāhmaṇena bhaveccīrṇaṃ vrataṃ dvādaśavārṣikamitareṣāṃ tu varṇānāṃ sarvapāpaṃ praṇaśyati

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