Mahabharata Sauptika Parva Chapter 11:2

Mahabharata Sauptika Parva Chapter 11:2 "Having said these words unto the royal son of Pandu, the beautiful Krishna approached Bhimasena and said these words of high purpose unto him: 'Remembering the duties of a Kshatriya, O Bhima, it behoveth thee to come to my rescue. Slay that man of sinful deeds like Maghavat slaying Samvara. There is no one in this world who is equal to thee in prowess. It is known throughout the world how on an occasion of great calamity thou becamest at the town Varanavata the refuge of all the Parthas. When again we were seen by Hidimba, it was thou that becamest our refuge in the same way. Like Maghavat rescuing (his spouse) the daughter of Puloma, thou didst rescue my afflicted self, in Virata's city, from a great calamity. Like those great feats, O Partha, that thou didst achieve in former days, slay now, O slayer of foes, the son of Drona and be thou happy!' "Hearing these and other piteous lamentations of the princess, Kunti's son, Bhimasena, of great might, could not endure them. He mounted upon his great car adorned with gold and took his beautiful bow with arrow placed on the string. Making Nakula his charioteer, and resolved upon slaying the son of Drona, he began to stretch his bow and caused his steeds to be urged without delay. Those steeds, fleet as the wind, thus urged, O tiger among men, proceeded with great speed. Possessed of great valour and unfading energy, Bhima set out from the Pandava camp and proceeded with great celerity along the track of Ashvatthama's vehicle."