Mbh 7.11.1d

On earth they are seen by men as two separate forms, though in reality they are both possessed but by one soul. With the mind alone, that invincible pair, of world-wide fame, can, if only they wish it, destroy this host. Only, in consequence of their humanity they do not wish it.[23] Like a change of the Yuga, the death of Bhishma, O child, and the slaughter of the high-souled Drona, overturn the senses. Indeed, neither by Brahmacharya, nor by the study of the Vedas, nor by (religious) rites, nor by weapons, can any one prevent death. Hearing of the slaughter of Bhishma and Drona, those heroes accomplished in weapons, respected by all the worlds, and invincible in battle, why O Sanjaya, do I yet live? In consequence of the death of Bhishma and Drona, O Sanjaya, we will henceforth have to live as dependants on that prosperity beholding which in Yudhishthira we had before been so jealous. Indeed, this destruction of the Kurus hath come in consequence only of my acts. O Suta, in killing these that are ripe for destruction, the very straw becomes thunderbolt. That prosperity is without end in this world which Yudhishthira is about to obtain--Yudhishthira through whose wrath both Bhishma and Drona have fallen. In consequence of his very disposition, hath Righteousness gone over to the side of Yudhishthira, while it is hostile to my son. Alas, time, so cruel, that hath now come for the destruction of all, cannot be overcome. Things calculated in one way, O son, even by men of intelligence, become otherwise through Destiny. This is what I think. Therefore, tell me everything that has taken place during the progress of this unavoidable and dreadful calamity productive of the most sorrowful reflection incapable of being crossed over (by us).’”