Tirukkural 312: Not Doing Evil

It is the determination of the spotless not to do evil, even in return, to those who have cherished enmity and done them evil.

Image of Satguru Sivaya Subramuniyaswami
The guru helps the devotee to hold his mind in focus, to become pointedly conscious of thought, word and deed, and to cognize the lessons of each experience.
—Gurudeva