The Lord God Almighty is a God of vengeance, and when he says "vengeance is mine" he means it. He not only intends to execute vengeance on the enemy, he expects and intends that you will also, through the power of the indwelling Holy Spirit Of God. Vengeance is not unforgiveness, because unforgiveness blackens the soul, while vengeance heals it. Unforgiveness demands recompense, while vengeance seeks it. Unforgiveness claims defeat, but vengeance claims victory. And unforgiveness is self-protective, while vengeance seeks the good of all.
If you are uncomfortable with the idea of seeking vengeance, the Lord God Almighty will never compel you to do so. You should know, however, that without vengeance, there is no healing. Vengeance is necessary, in fact, mandatory, if you are to become who God created you to be.
The Lord God Almighty El Shaddai