Mbh 7.193.1d

He for whom thou hast taken up weapons, and for whom thou livest, he, deprived of life, lieth today on the field of battle, unknown to thee and behind thy back. King Yudhishthira the just hath told thee this. It behoveth thee not to doubt this fact.” Thus addressed by Bhima, Drona laid aside his bow. Desirous of laying aside all his weapons also, Bharadwaja’s son of virtuous soul said aloud, “O Karna, Karna, O great bowman, O Kripa, O Duryodhana, I tell you repeatedly, exert yourselves carefully in battle. Let no injury happen to you from the Pandavas. As regards myself, I lay aside my weapons.” Saying these words, he began loudly to take the name of Aswatthaman. Laying aside his weapons then in that battle, and sitting down on the terrace of his car, he devoted himself to Yoga and assured all creatures, dispelling their fears. Beholding that opportunity, Dhrishtadyumna mustered all his energy. Laying down on the car his formidable bow, with arrow fixed on the bow-string, he took up a sword, and jumping down from his vehicle, rushed quickly against Drona. All creatures, human beings and others, uttered exclamation of woe, beholding Drona thus brought under Dhrishtadyumna’s power. Loud cries of Oh and Alas were uttered, as also those of Oh and Fie. As regards Drona himself, abandoning his weapons, he was then in a supremely tranquil state. Having said those words he had devoted himself to Yoga. Endued with great effulgence and possessed of high ascetic merit, he had fixed his heart on that Supreme and Ancient Being, viz., Vishnu.