Kural - 870

The task of angry war with men unlearned in virtue's lore
Who will not meet, glory shall meet him never more

Explanation
The light (of fame) will never be gained by him who gains not the trifling reputation of having fought an unlearned (foe).

Tamil Transliteration
Kallaan Vekulum Siruporul Egngnaandrum
Ollaanai Ollaa Tholi.