Kural - 488

If foes' detested form they see, with patience let them bear;
When fateful hour at last they spy,- the head lies there

Explanation
If one meets his enemy, let him show him all respect, until the time for his destruction is come; when that is come, his head will be easily brought low.

Tamil Transliteration
Serunaraik Kaanin Sumakka Iruvarai
Kaanin Kizhakkaam Thalai.