Kural - 679

Than kindly acts to friends more urgent thing to do,
Is making foes to cling as friends attached to you

Explanation
One should rather hasten to secure the alliance of the foes (of one's foes) than perform good offices to one's friends.

Tamil Transliteration
Nattaarkku Nalla Seyalin Viraindhadhe
Ottaarai Ottik Kolal.