Mbh 12.138.5e

Possessed of the strength of policy, thou hast given us our life.' Addressed in such soothing words by the cat, the mouse, conversant with all that is productive of the highest good, replied in these sweet words that were beneficial to himself: 'I have heard, O Lomasa, all that thou hast said. Listen now as I say what appears to me. Friends should be well examined. Foes also should be well studied. In this world, a task like this is regarded by even the learned as a difficult one depending upon acute intelligence. Friends assume the guise of foes, and foes assume the guise of friends. When compacts of friendship are formed, it is difficult for the parties to understand whether the other parties are really moved by lust and wrath. There is no such thing as a foe. There is no such thing in existence as a friend. It is force of circumstances that creates friends and foes. He who regards his own interests ensured as long as another person lives and thinks them endangered when that other person will cease to live, takes that other person for a friend and considers him so as long as those interests of his are not clashed against. There is no condition that deserves permanently the name either of friendship or hostility. Both friends and foes arise from considerations of interest and gain. Friendship becomes changed into enmity in the course of time. A foe also becomes a friend. Self-interest is very powerful. He who reposes blind trust on friends and always behaves with mistrust towards foes without paying any regard to considerations of policy, finds his life to be unsafe. He who, disregarding all considerations of policy, sets his heart upon an affectionate union with either friends or foes, comes to be regarded as a person whose understanding has been unhinged. One should not repose trust upon a person undeserving of trust, nor should one trust too much a person deserving of trust.