Mbh 3.215.2a

“The fowler replied, ‘The bodily afflictions should be cured with medicines, and the mental ones with spiritual wisdom. This is the power of knowledge. Knowing this, the wise should not behave like boys. Man of low intelligence are overpowered with grief at the occurrence of something which is not agreeable to them, or non-occurrence of something which is good or much desired. Indeed, all creatures are subject to this characteristic (of grief or happiness). It is not merely a single creature or class that is subject to misery. Cognisant of this evil, people quickly mend their ways, and if they perceive it at the very outset they succeed in curing it altogether. Whoever grieves for it, only makes himself uneasy. Those wise men whose knowledge has made them happy and contented, and who are indifferent to happiness and misery alike, are really happy. The wise are always contented and the foolish always discontented. There is no end to discontentment, and contentment is the highest happiness. People who have reached the perfect way, do not grieve, they are always conscious of the final destiny of all creatures. One must not give way to discontent[57] for it is like a virulent poison. It kills persons of undeveloped intelligence, just as child is killed by an enraged snake. That man has no manliness whose energies have left him and who is overpowered with perplexity when an occasion for the exercise of vigour presents itself. Our actions are surely followed by their consequences. Whoever merely gives himself up to passive indifference (to worldly affairs) accomplishes no good. Instead of murmuring one must try to find out the way by which he can secure exemption from (spiritual) misery; and the means of salvation found, he must then free himself from sensuality. The man who has attained a high state of spiritual knowledge is always conscious of the great deficiency (instability) of all matter.