The very same Torah which warns us not to take revenge describes G‑d Himself as “a vengeful G‑d.” How can this be? If we are told not to be vengeful, if revenge is immoral, how can G‑d be vengeful?
But that is exactly the point. The very fact that G‑d is vengeful allows us humans not to be. No human justice system is foolproof, so ultimate justice is in His hands. He will right the wrongs and punish the wicked. In this world or in the next, in this lifetime or another, in ways we may never know, justice will be served.
It’s funny, you often hear people disparaging “the vengeful G‑d of the Bible.” They somehow think that a vengeful G‑d will produce vengeful followers. The opposite is true. It is precisely G‑d’s vengefulness that enables humans to let go of the desire for revenge. We know there is a true Judge, and He will do justice. So we humans can leave the vengeance to Him, and get on with living.
Credits: Rabbi Moss, Chabad.org, Menachem Mendel Bluming