"If this law of Karma, "an eye for an eye, and a tooth for a tooth," is inevitable and exact justice, it by no means follows that we ourselves, personally, should attempt to fulfil it in this way. If we do so, we shall never emerge from the magic circle of karma. Indeed, we must forgive our personal enemies, as who knows but that the blow one receives is a return blow, well-deserved under the law of Karma? By returning such a blow with another and with a feeling of revenge in our heart, we do not outlive this karma, but we continue and even intensify it in the worst way for ourselves. Moreover, by forgiving our enemies we decrease the amount of evil in space and become immune against many blows. Similarly, let us understand the words "Love thine enemies." However, with all this, we must resist evil, if we do not want to be entirely overwhelmed by it. (26 May 1934)"
January 1, 1970
https://en.wikiquote.org/wiki/Enemies