Kural - 364

Desire's decease as purity men know;
That, too, from yearning search for truth will grow

Explanation
Purity (of mind) consists in freedom from desire; and that (freedom from desire) is the fruit of the love of truth.

Tamil Transliteration
Thoouymai Enpadhu Avaavinmai Matradhu
Vaaaimai Venta Varum.