How do we know that God's wrath is justified?

The justification for God's wrath lies in His holy and unchanging nature. As expressed in Romans 2, God’s wrath reveals His justice against all unrighteousness. It is a fundamental aspect of His holiness that He must react against sin because His nature is entirely good and just. If God were to ignore or overlook sin, He would not be just, which contradicts His very being. Therefore, God's wrath is not arbitrary but is essential for upholding the moral order and justice within creation.