Kural - 584

His officers, his friends, his enemies,
All these who watch are trusty spies

Explanation
He is a spy who watches all men, to wit, those who are in the king's employment, his relatives, and his enemies.

Tamil Transliteration
Vinaiseyvaar Thamsutram Ventaadhaar Endraangu
Anaivaraiyum Aaraaivadhu Otru.