Kural - 134

Though he forget, the Brahman may regain his Vedic lore;
Failing in 'decorum due,' birthright's gone for evermore

Explanation
A Brahman though he should forget the Vedas may recover it by reading; but, if he fail in propriety of conduct even his high birth will be destroyed.

Tamil Transliteration
Marappinum Oththuk Kolalaakum Paarppaan
Pirappozhukkang Kundrak Ketum.