Kural - 971

The light of life is mental energy; disgrace is his
Who says, 'I 'ill lead a happy life devoid of this.'

Explanation
One's light is the abundance of one's courage; one's darkness is the desire to live destitute of such (a state of mind.).

Tamil Transliteration
Olioruvarku Ulla Verukkai Ilioruvarku
Aqdhirandhu Vaazhdhum Enal.