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
Giving a gift begrudgingly in return for another gift is, of course, mere barter. Many families barter their way through life in this way, thinking they are giving. But such gifts are cold, the fulfillment is empty, and the law of karma pays discounted returns.
—Gurudeva