Mbh 5.188.2a

“‘Bhishma continued, “Thus addressed by his own ancestors, Rama answered them, saying, ‘I cannot give up the combat. Even this is the solemn vow I have made. Before this, I never left the field, giving up battle! Ye grandsires, if you please, cause Ganga’s son to desist from the fight! As regards myself, I can, by no means, desist from the combat!’ Hearing these words of his, O king, those ascetics with Richika at their head, coming to me with Narada in their company, told me, ‘O sire, desist from battle! Honour that foremost of Brahmanas!’ For the sake of Kshatriya morality, I replied unto them, saying, ‘Even this is the vow I have taken in this world, viz., that I would never desist from battle turning my back, or suffer my back to be wounded with arrows! I cannot, from temptation or distress, or fear, or for the sake of wealth, abandon my eternal duty! Even this is my fixed resolution!’ Then all those ascetics with Narada at their head, O king, and my mother Bhagirathi, occupied the field of battle (before me). I, however, stayed quietly with arrows and bow as before, resolved to fight. They then once more turned towards Rama and addressed him, saying, ‘The hearts of Brahmanas are made of butter. Be pacified, therefore, O son of Bhrigu’s race! O Rama, O Rama, desist from this battle, O best of Brahmanas! Bhishma is incapable of being slain by thee, as indeed, thou, O Bhargava, art incapable of being slain by him!’ Saying these words while they stood obstructing the field, the Pitris caused that descendant of Bhrigu’s race to place aside his weapons. Just at this time I once more beheld those eight utterers of Brahma, blazing with effulgence and resembling bright stars risen on the firmament. Stationed for battle as I was, they said these words unto me with great affection, ‘O thou of mighty arms, go unto Rama who is thy preceptor! Do what is beneficial to all the worlds.’