Mbh 1.142.9a

“Kanika continued, ‘If thy son, friend, brother, father, or even the spiritual preceptor, anyone becometh thy foe, thou shouldst, if desirous of prosperity, slay him without scruples. By curses and incantations, by gift of wealth, by poison, or by deception, the foe should be slain. He should never be neglected from disdain. If both the parties be equal and success uncertain, then he that acteth with diligence groweth in prosperity. If the spiritual preceptor himself be vain, ignorant of what should be done and what left undone, and vicious in his ways, even he should be chastised. If thou art angry, show thyself as if thou art not so, speaking even then with a smile on thy lips. Never reprove any one with indications of anger (in thy speech). And O Bharata, speak soft words before thou smitest and even while thou art smiting! After the smiting is over, pity the victim, and grieve for him, and even shed tears. Comforting thy foe by conciliation, by gift of wealth, and smooth behaviour, thou must smite him when he walketh not aright. Thou shouldst equally smile the heinous offender who liveth by the practice of virtue, for the garb of virtue simply covereth his offences like black clouds covering the mountains. Thou shouldst burn the house of that person whom thou punishest with death. And thou shouldst never permit beggars and atheists and thieves to dwell in thy kingdom. By a sudden sally or pitched battle by poison or by corrupting his allies, by gift of wealth, by any means in thy power, thou shouldst destroy thy foe. Thou mayest act with the greatest cruelty. Thou shouldst make thy teeth sharp to give a fatal bite. And thou should ever smite so effectually that thy foe may not again raise his head. Thou shouldst ever stand in fear of even one from whom there is no fear, not to speak of him from whom there is such. For if the first be ever powerful he may destroy thee to the root (for thy unpreparedness).