Thirukkural 107

எழுமை எழுபிறப்பும் உள்ளுவர் தங்கண் விழுமந் துடைத்தவர் நட்பு.

Ezhumai ezhupirapum ulluvar tangkaN vizhumam tudaittavar natpu.

The friendship of those who have wiped away their shame holds firm through seventy births. Guard such bonds as you would guard your own integrity.