Mbh 6.96.1a

Sanjaya said, “After that great battle, king Duryodhana, approaching Ganga’s son and saluting him with humility, began to narrate to him all that had happened about the victory won by Ghatotkacha and his own defeat. That invincible warrior, O king, sighing repeatedly, said these words unto Bhishma, the grandsire of the Kurus, ‘O lord, relying upon thee, as Vasudeva hath been (relied upon) by the foe, a fierce war hath been commenced by me with the Pandavas. These eleven Akshauhinis of celebrated troops that I have, are, with myself, obedient to thy command, O chastiser of foes. O tiger among the Bharatas, though thus situated, yet have I been defeated into battle by the Pandava warriors headed by Bhimasena relying upon Ghatotkacha. It is this that consumeth my limbs like fire consuming dry tree. O blessed one, O chastiser of foes, I therefore desire, through thy grace, O grandsire, to slay Ghatotkacha myself, that worst of Rakshasas, relying upon thy invincible self. It behoveth thee to see that wish of mine may be fulfilled.’ Hearing these words of the king, that foremost one among the Bharatas, viz., Bhishma, the son of Santanu, said these words unto Duryodhana, ‘Listen, O king, to these words of mine that I say unto thee, O thou of Kuru’s race, about the way in which thou, O chastiser of foes, shouldst always behave. One’s own self, under all circumstances, should be protected in battle, O repressor of foes. Thou shouldst always, O sinless one, battle with king Yudhishthira the Just, or with Arjuna, or with the twins, or with Bhimasena. Keeping the duty of a king before himself, a king striketh a king. Myself, and Drona, and Kripa, and Drona’s son, and Kritavarman of the Satwata race, and Salya, and Somadatta’s son, and that mighty car-warrior Vikarna, and thy heroic brothers headed by Dussasana, will all, for thy sake, battle against that mighty Rakshasas.