Mbh 5.75.1a

Vaisampayana said, “Hearing these words from Bhima, that were fraught with such mildness and that were, as unexpected as if the hills had lost their weight and fire had become cold, Rama’s younger brother Kesava of Sura’s race and mighty arms, wielding the bow called Saranga, laughed aloud, and as if to stimulate Bhima by his words, like the breeze fanning a fire, addressed him who was then so overwhelmed by the impulse of kindness, saying, ‘At other times, O Bhimasena, thou applaudest war only, desirous of crushing the wicked sons of Dhritarashtra that take delight in the destruction of others. O chastiser of foes, thou dost not sleep but wakest the whole night, sitting up face downwards. Thou often utterest frightful exclamation of wrath, indicative of the storm within thy heart. Inflamed with the fire of thy own fury, thou sighest, O Bhima with an unquiet heart, like a flame of fire mixed with smoke. Withdrawing from company thou liest down breathing hot sighs, like a weak man pressed down by a heavy load. They, who do not know the cause regard thee as insane. As an elephant breaking into fragments uprooted trees lying on the ground grunteth in rage while trampling them under his feet, so thou also, O Bhima, runnest on, breathing deep sighs and shaking the earth under thy tread. Here in the region thou takest no delight in company but passest thy time in privacy. Night or day, nothing pleases thee so much as seclusion. Sitting apart thou sometimes laughest aloud all on a sudden, and sometimes placing thy head between thy two knees, thou continuest in that posture for a long time with closed eyes. At the other times, O Bhima, contracting thy brows frequently and biting thy lips, thou starest fiercely before thee. All this is indicative of wrath.