Kural - 993

Men are not one because their members seem alike to outward view;
Similitude of kindred quality makes likeness true

Explanation
Resemblance of bodies is no resemblance of souls; true resemblance is the resemblance of qualities that attract.

Tamil Transliteration
Uruppoththal Makkaloppu Andraal Veruththakka
Panpoththal Oppadhaam Oppu.