Mbh 7.191.1a

“Sanjaya said, ‘Then Drona caused a great carnage among the Panchalas, like the slaughter caused by Sakra himself in rage amongst the Danavas in the days of yore. The great car-warriors of the Pandava army, endued with might and energy, though slaughtered, O king, by Drona’s weapons, were not yet afraid of Drona in that battle. Indeed, O monarch, those mighty car-warriors, viz., the Panchalas and the Srinjayas, all rushed against Drona himself, for fighting with him. Loud and fierce were the yells they uttered as they rushed towards Drona for encompassing him on all sides and were slaughtered by him with shafts and darts. Beholding the slaughter of the Panchalas in that battle by the illustrious Drona, and seeing his weapons overwhelm all sides, fear entered the hearts of the Pandavas. Beholding that dreadful carnage of steeds and human beings in that battle, the Pandavas, O monarch, became hopeless of victory. (They began to say unto each other) “Is it not evident that Drona, that warrior conversant with the mightiest of weapons, will consume us all like a raging conflagration consuming a heap of straw in the season of spring? There is none competent to even look at him in battle. Conversant with the ways of morality, Arjuna (who alone is a match for him) will not fight with him.” Beholding the sons of Kunti afflicted with the shafts of Drona and inspired with fear, Kesava, endued with great intelligence and devoted to their welfare, addressed Arjuna and said, “This foremost of all bowmen is incapable of being ever vanquished by force in battle, by the very gods with Vasava at their head. When, however, he lays aside his weapons, he becomes capable of being slain on the field even by human beings. Casting aside virtue, ye sons of Pandu, adopt now some contrivance for gaining the victory, so that Drona of the golden car may not slay us all in battle. Upon the fall of (his son) Aswatthaman he will cease to fight, I think.