Mbh 4.38.1a

Vaisampayana said, “Having issued forth from the city, the dauntless son of Virata addressed his charioteer, saying, ‘Proceed whither the Kurus are. Defeating the assembled Kurus who have come hither from desire of victory, and quickly rescuing my kine from them, I will return to the capital.’ At these words of the prince, the son of Pandu urged those excellent steeds. And endued with the speed of the wind and decked with necklaces of gold, those steeds, urged by that lion among men, seemed to fly through the air. And they had not proceeded far when those smiters of foes, Dhananjaya and the son of Matsya, sighted the army of the powerful Kurus. And proceeding towards the cemetery, they came upon the Kurus and beheld their army arrayed in order of battle.[40] And that large army of theirs looked like the vast sea or a forest of innumerable trees moving through the sky. And then was seen, O best among the Kurus, the dust raised by that moving army which reached the sky and obstructed the sight of all creatures. And beholding that mighty host abounding in elephants, horses and chariots, and protected by Karna and Duryodhana and Kripa and Santanu’s son, and that intelligent and great bowman Drona, with his son (Aswatthaman), the son of Virata, agitated with fear and the bristles on his body standing on their ends, thus spake unto Partha, ‘I dare not fight with the Kurus. See, the bristles on my body have stood on their ends. I am incapable of battling with this countless host of the Kurus, abounding in the heroic warriors, that are extremely fierce and difficult of being vanquished even by the celestials. I do not venture to penetrate into the army of the Bharatas consisting of terrible bowmen and abounding in horses and elephants and cars and footsoldiers and banners.