Eknath Easwaran's Commentary
When you feel angry towards someone and want to say something unkind, that is all the more reason to speak kindly. If someone provokes you and you respond with anger, you are reinforcing anger as a part of your personality.
So returning kindness for unkindness is not simply being kind to that particular person. You’re being kinder to yourself, because you are undoing a compulsion, taking one more step towards being free. You are turning wrath away from yourself, as well as being kind to the other person.
The deconditioning process is straightforward enough: when anger comes up, don’t act on it. When it tries to tell you what to do, say no. Repeat the mantram, go out for a long, brisk walk if possible, and throw yourself into hard, concentrated work, preferably for the benefit of others. When you can shift your attention to your work or to the mantram, you have shifted it away from the anger. Immediately the anger-tendency is weakened a little.