Kural - 961

Though linked to splendours man no otherwise may gain,
Reject each act that may thine honour's clearness stain

Explanation
Actions that would degrade (one's) family should not be done; though they may be so important that not doing them would end in death.

Tamil Transliteration
Indri Amaiyaach Chirappina Aayinum
Kundra Varupa Vital.