Thirukkural 686

கற்றுக்கண் அஞ்சான் செலச்சொல்லிக் காலத்தால் தக்கது அறிவதாம் தூது.

Kattrukkan anjaan selacchollik kaalaththaal thakkadhu arivadhaadaam thoodu.

An emissary speaks without fear to one who has learned, times his words with precision, and knows what is fitting—this is the skill of the envoy.