Kural - 658

To those who hate reproof and do forbidden thing
What prospers now, in after days shall anguish bring

Explanation
The actions of those, who have not desisted from doing deeds forbidden (by the great), will, even if they succeed, cause them sorrow.

Tamil Transliteration
Katindha Katindhoraar Seydhaarkku Avaidhaam
Mutindhaalum Peezhai Tharum.