Kural - 859

Men think not hostile thought in fortune's favouring hour,
They cherish enmity when in misfortune's power

Explanation
At the approach of wealth one will not think of hatred (but) to secure one's ruin, one will look to its increase.

Tamil Transliteration
Ikalkaanaan Aakkam Varungaal Adhanai
Mikalkaanum Ketu Thararku.