Kural - 659

What's gained through tears with tears shall go;
From loss good deeds entail harvests of blessings grow

Explanation
All that has been obtained with tears (to the victim) will depart with tears (to himself); but what has been by fair means; though with loss at first, will afterwards yield fruit.

Tamil Transliteration
Azhak Konta Ellaam Azhappom Izhappinum
Pirpayakkum Narpaa Lavai.