Mbh 12.25.4c

When sorrow must arise upon the expiration of happiness, and happiness upon the expiration of sorrow, one should, for that, cast off, like a (snake-bit) limb of one's body, that from which one experiences sorrow or that heart-burning which is nurtured by sorrow or that which is the root of his anxiety.[75] Be it happiness or sorrow, be it agreeable or disagreeable, whatever comes should be borne with an unaffected heart. O amiable one, if thou abstainest, in even a slight measure, from doing what is agreeable to your wives and children, thou shalt then know who is whose and why so and for what. They that are highly stupid and they that are masters of their souls enjoy happiness here. They however, that occupy an intermediate place suffer misery. This, O Yudhishthira, is what Senajit of great wisdom said, that person who was conversant with what is good or bad in this world, with duties, and with happiness and misery. He who is grieved at other people's griefs can never be happy. There is no end of grief, and grief arises from happiness itself. Happiness and misery, prosperity and adversity, gain and loss, death and life, in their turn, wait upon all creatures. For this reason the wise man of tranquil soul should neither be elated with joy nor be depressed with sorrow. To be engaged in battle has been said to be the Sacrifice for a king; a due observance of the science of chastisement is his Yoga; and the gift of wealth in sacrifices in the form of Dakshina is his Renunciation. All these should be regarded as acts that sanctify him. By governing the kingdom with intelligence and policy, casting off pride, performing sacrifices, and looking at everything and all persons with kindness and impartiality, a high-souled king, after death, sports in the region of the gods.