Kural - 319

If, ere the noontide, you to others evil do,
Before the eventide will evil visit you

Explanation
If a man inflict sorrow upon others in the morning, it will come upon him unsought in the very evening.

Tamil Transliteration
Pirarkkinnaa Murpakal Seyyin Thamakku Innaa
Pirpakal Thaame Varum.