He that keeps malice harbors a viper in his breast

Most religions and many schools of psychology teach the importance of forgiveness. The problem with bearing grudges is that they can distort the personality and over time make a person prone to depression and ill health.

Now, it seems to be counter intuitive to be totally forgiving, and commonnsense does seem to bear out that if you are weak you are more likely to be attacked. It follows that the knowledge that you have the capacity to retaliate and are prepared to do so if neccessary will often deter an enemy from attacking you. Speak softly and carry a big stick.

But sometimes you have to be wise for two. If you can rise above knee-jerk retaliation, and have an inside understanding of a situation, and the reasons for the attack, you might be able to see that by understanding and forgiving your enemy you could turn them into a friend. It might just pay you to take a loss and prevent a tit-for-tat escalation.

This requires judgement and insight and is a mark of true wisdom.