Kural - 843

With keener anguish foolish men their own hearts wring,
Than aught that even malice of their foes can bring

Explanation
The suffering that fools inflict upon themselves is hardly possible even to foes.

Tamil Transliteration
Arivilaar Thaandhammaip Peezhikkum Peezhai
Seruvaarkkum Seydhal Aridhu.