Mbh 12.56.4b

If a Brahmana becomes guilty of Brahmanicide, or of violating the bed of his preceptor or other revered senior, or of causing miscarriage, or of treason against the king, his punishment should be banishment from thy dominions. No corporal chastisement is laid down for them. Those persons that show respect towards the Brahmanas should be favoured by thee (with offices in the state). There is no treasure more valuable to kings than that which consists in the selection and assemblage of servants. Among the six kinds of citadels indicated in the scriptures, indeed among every kind of citadel, that which consists of (the ready service and the love of the) subjects is the most impregnable. Therefore, the king who is possessed of wisdom should always show compassion towards the four orders of his subjects. The king who is of righteous soul and truthful speech succeeds in gratifying his subjects. Thou must not, however, O son always behave with forgiveness towards everybody, for the king that is mild is regarded as the worst of his kind like an elephant that is reft of fierceness. In the scriptures composed by Vrihaspati, a Sloka was in days of old applicable to the present matter. Hear it, O king as I recite it. 'If the king happens to be always forgiving, the lowest of persons prevails over him, even as the driver who sits on the head of the elephant he guides.' The king, therefore, should not always be mild. Nor should he always be fierce. He should be like the vernal Sun, neither cold nor so hot as to produce perspiration. By the direct evidence of the senses, by conjecture, by comparisons, and by the canons of the scriptures. O monarch, the king should study friends and foes. O thou of great liberality, thou shouldst avoid all those evil practices that are called Vyasanas. It is not necessary that thou shouldst never indulge in them. What, however, is needed is that thou shouldst not be attached to them.