The Great Epic of the Bhārata dynasty 6.2.9

6.2.9

vyāsa uvāca |
eṣa te saṃjayo rājanyuddhametadvadiṣyati |
etasya sarvaṃ saṃgrāme naparokṣaṃ bhaviṣyati || 9 ||

Vaisampayana continued.--"Upon his not wishing to see the battle but wishing to hear of it, Vyasa, that lord of boons, gave a boon to Sanjaya. (And addressing Dhritarashtra he said),--'This Sanjaya, O king, will describe the battle to thee. Nothing in the whole battle will be beyond this one's eyes.' Endued, O king with celestial vision, Sanjaya will narrate the battle to thee. He will have knowledge of everything. Manifest or concealed, (happening) by day or by night, even that which is thought of in the mind, Sanjaya shall know everything. Weapons will not cut him and exertion will not fatigue him. This son of Gavalgani will come out of the battle with life. As regards myself, O bull of Bharata's race, the fame of these Kurus, as also of all the Pandavas, I will spread. Do not grieve. This is destiny, O tiger among men. It behoveth thee not to give way to grief. It is not capable of being prevented. As regards victory, it is there where righteousness is.'"