Do not take revenge. (Vayikra 19:18)
It says in Sefer Mesilas Yesharim that it is very hard for the human heart to free itself of vengefulness, because people are very sensitive to insult. It hurts them a lot, and revenge feels sweeter than honey, because it eases them.
Why is it so very sweet to get even with the one who hurt you and put you down? Let’s say Reuven wronged Shimon. What does Shimon actually gain by avenging himself on Reuven?
The answer is Shimon gains a lot. When he gets back at Reuven and settles accounts, he retroactively removes the humiliation and the smirch to his name that was perpetrated on him yesterday. It shows that Reuven never had the right to treat him that way in the first place, because now all can see that Reuven is paying for it dearly.
This is sweeter than honey because it retroactively removes the blemish to Shimon’s honor.
But the Torah tells us not to do it. לא תקום – “Do not take revenge.” Why not? Because we need to recognize the truth: had it not been decreed in Heaven, the other person would never have been able to treat us that way.
There is no prohibition on guarding oneself from further harm. A person is allowed to protect himself from hurt and damage. But what happened yesterday, it already happened. Although the deed cannot be undone, we might be tempted to change what it means, and show retroactively that it was wrong, that it was unfair. Regarding this, the Torah tells us no, don’t do it. Don’t take revenge. Instead, we should recognize that everything is decreed by Heaven. No one down here does anything that was not decreed up there.
By contrast, Hashem is called ת ה' ֹמוָקְ־ל נֵא – “Hashem is a G-d of requital.”
Not only is it proper and fitting for Hashem to pay back evildoers for their deeds, it is even necessary, due to Hashem’s absolute Oneness.
How so?
Let’s say a person sins against Hashem one day and stops sinning the next day. Yesterday he acted against Hashem’s Will and today he did Hashem’s Will.
This contradicts Hashem’s Oneness, because Hashem always ruled and always will rule. He is in control of every single moment and every single action. There can’t be a moment or an action that is out of Hashem’s domain.
Every deed that appears to be against Hashem’s Will must meet with punishment and reprisal, because this is the only way to remove the deed retroactively and demonstrate for all to see what it means to act against Hashem’s Will; it means the perpetrator will pay for it dearly, he will hurt and suffer for it. This shows that there is no such thing as going against Hashem, and retroactively rectifies the deed.
