Tiruvalluvar

“ Though malice work its worst, planning no ill return, to endure,
And work no ill, is fixed decree of men in spirit pure.
It is the determination of the spotless not to do evil, even in return, to those who have cherished enmity and done them evil. ”

“ Let not a man consent to do those things to another which, he knows, will cause sorrow.
Kural - 317
To work no wilful woe, in any wise, through all the days,
To any living soul, is virtue's highest praise.
It is the chief of all virtues not knowingly to do any person evil, even in the lowest degree, and at any time.
Kural - 318
Whose soul has felt the bitter smart of wrong, how can
He wrongs inflict on ever-living soul of man?
Why does a man inflict upon other creatures those sufferings, which he has found by experience are sufferings to himself ? ”