Bhishma said Let those Brahmanas eat, moved by desire, who observe such vows as are not laid down in the Vedas. About those Brahmanas, however, who observe such vows as are laid down in the Vedas, they are considered as guilty of a breach of their vow, O Yudhishthira, by eating the Havi of Shraddha at the request of him who performs the Shraddha.
भीष्म उवाच अवदोक्तव्रताश्चैव भुजानाः कामकारणे। वेदोक्तेषु तु भुजाना व्रतलुप्ता युधिष्ठिर॥