Kural - 804

When friends unbidden do familiar acts with loving heart,
Friends take the kindly deed in friendly part

Explanation
If friends, through the right of friendship, do (anything) without being asked, the wise will be pleased with them on account of its desirability.

Tamil Transliteration
Vizhaidhakaiyaan Venti Iruppar Kezhudhakaiyaar
Kelaadhu Nattaar Seyin.