The apostle Paul speaks of God dealing with individuals with both "goodness" and "severity" (Rom. 11:22). Of course, the circumstances dictate which God will use in a given situation. "Forbearance" and "longsuffering" demonstrate His goodness and are intended to lead us to repentance (Rom. 2:4-11). Those who are faithful and obedient will be blessed with "eternal life" (vs. 7, 10). Those with hard, impenitent hearts will face God's "wrath" (vs. 5, 8-9). His "wrath" demonstrates God's severity; it is "against all ungodliness and unrighteousness of men..." (Rom. 1:18).
God's wrath is not such as would be demonstrated by a human being. It is not uncontrolled rage. It is not mean-spirited hatred. It is not seated in evil. God's wrath is righteous and justified and deserved. It is focused upon the person who lives an ungodly life in spite of all of God's blessings bestowed upon and His goodness displayed toward that person. It is God's response to a person's chosen life of unrighteousness and sin.
Paul wrote something quite telling in his first letter to the Thessalonians: "For God did not appoint us to wrath, but to obtain salvation through our Lord Jesus Christ" (1 Thess. 5:9). The next verse notes that Christ "died for us." That death was on the cross to pay the price for the guilt of our sin, and it was specifically directed by God. God did that for us, that we might be redeemed from the condemnation of our own sin. When we, in a sense, throw that sacrifice back in God's face by continuing to live in sin, we deserve His wrath!
Someone might think that wrath is beneath a loving, merciful God of grace, that such a God would not resort to wrath. But that line of thinking ignores the reason that calls for and justifies the wrath - the terribleness of sin! Sin is not incidental; it is not a minor matter. Sin sullied the unique, divine image in which man was created. Sin is eternally destructive. Because God recognized these facts, He devised the way, through the death of His own Son, for man to be cleansed, forgiven, reconciled. God's wrath is a reflection of the horrible awfulness of sin...