Mahabharata Drona Parva Chapter 197:2

Mahabharata Drona Parva (Drona-vadha Parva) Chapter 197:2 This terrific uproar, making the hair stand on end, that is now heard, would, it seems, swallow the three worlds with Indra at their head. I think this terrible uproar is uttered by the wielder of the thunderbolt himself. It is evident that upon the fall of Drona, Vasava himself is approaching (against us) for the sake of the Kauravas. Our hairs have stood on their ends, our foremost of car-warriors are all afflicted with anxiety. O Dhananjaya, hearing this loud and terrible noise, I ask thee who is that mighty car-warrior, like the lord of the celestials himself, that rallying this terrible and swelling host, is causing it to return? Arjuna said, "He, relying upon whose energy the Kauravas, having addressed themselves to the accomplishment of fierce feats, are blowing their conchs and staying with patience, he about whom thou hast thy doubts, O king, as to who he may be that is roaring so loud, having rallied the Dhartarashtras after the fall of the disarmed preceptor, he, who is endued with modesty, possessed of mighty arms, has the tread of an infuriated elephant, owns a face like that of a tiger, always achieves fierce feats, and dispels the fears of the Kurus, he upon whose birth Drona gave away a thousand kine unto Brahmanas of high worth, he O king, that is roaring so loud, is Aswatthaman. As soon as he was born, that hero neighed like Indra's steed and caused the three worlds to tremble at that sound. Hearing that sound, an invisible being, O lord, (speaking audibly) bestowed upon him the name of Aswatthaman (the horse-voiced). That hero, O son of Pandu, is roaring today. Prishata's son, by an exceedingly cruel act, assailed Drona and took his life as if the latter was without a preceptor. Yonder stayeth the preceptor of that Drona. Since the prince of the Panchalas seized my preceptor by the hair, Aswatthaman, confident of his own prowess, will never forgive him. Thou, O monarch, hath told thy preceptor a falsehood for the sake of kingdom! Although thou art acquainted with the dictates of righteousness, thou hast yet perpetrated a very sinful act. Thy ill fame, in consequence of the slaughter of Drona, will be eternal in the three worlds with their mobile and immobile creatures, like Rama's in consequence of the slaughter of Bali! About thyself, Drona had thought, 'The son of Pandu is possessed of every virtue; he is, besides, my disciple. He will never speak an untruth to me.' Thinking so, he gave credence to what thou hadst said. Although in speaking of Aswatthaman's death thou hadst added the word elephant, yet thy answer to the preceptor was, after all, an untruth in the garb of truth. Thus told by thee, the puissant Drona laid aside his weapons and, as thou sawest, became indifferent (to everything), exceedingly agitated, and almost deprived of his senses. It was even a disciple who, abandoning all morality, thus slew his own preceptor, full of affection for his son, while, indeed, that preceptor was filled with grief and unwilling to fight. Having caused him, who had laid his weapons to be unrighteously slain, protect the son of Prishata if thou canst, with all thy counsellors.