The wrath of God is poured out on all unrighteousness. Any unrighteousness deserves God's wrath.
This is a glorious truth. It is not an easy truth, but it is the root of the Gospel. Because God hates evil, Christ came to destroy evil. Because God loves his glory, and in grace has called us to himself, his wrath is poured out on Christ instead of on us.
If God did not hate evil, then he would not have saved us from it.
We are all unrighteous, and so all deserves God's wrath. It is only in view of this fact, that we deserve God's wrath, that we have any desire for the Biblical Gospel. It is only when we see that we are lost, unable to save ourselves, that we begin to seek another to save us.
We must rely on Christ alone to save us, and we only do so when we are convinced that we are nothing.
Is it Gospel to say that we are nothing? Isn't it? We are often trying to avoid our feelings of guilt, of inadequacy, of worthlessness. The world tells us that these feelings are false, that we shouldn't feel this way, that we should have more self-esteem, but the Gospel's root is in the truthfulness of these feelings. We are nothing, we need not be afraid of acknowledging that fact, and we are therefore freed to rejoice in our weakness. We fear our unworth and weakness because we need to be presentable before God, our unworth and weakness keeps us from God. It is because we have no righteousness, however, that we need Christ's, and it is because we have Christ's righteousness that we no longer need to fear our own inadequacy. Our weakness magnifies God's strength. Our unrighteousness magnifies God's righteousness. When we see how great our sin, we see how great Christ's righteousness was, that he could work so great a salvation. Our salvation is magnified in light of how great our need for it is.
The Gospel of Jesus Christ saves us from the guilt of sin, and therefore from its power.
If we fear our sins, we cannot face them in battle by the strength of the Spirit which raised Jesus from the dead. The teeth of sin are removed by the removal of guilt. Our reliance on Christ's atoning work begins in recognition of our inability to work any good work. It continues as reliance in our reliance on him to work every good work in us. Our recognition of our inability does not stop our good works, but rather stops our reliance on our own power which is ineffective, and redirects us to rely on the power of the Holy Spirit who empowers and impels us to live as Christ lived.
Our recognition of the unrighteousness of our own works also frees us from them because as long as we fear our unrighteousness we must excuse it, or change it by our own ineffective power. We cannot truly acknowledge that we need to change in any lasting way if we do not acknowledge that how we are is not okay. If I seek to change myself, I will only be changed from one kind of unrighteousness to another, but if I seek, by the power of the Spirit, to be changed by God, then I will be changed from one degree of glory to another. For in the righteous holiness of God we perceive our sins and the beauty of his goodness, and so our desires are changed from unrighteousness to righteousness. When we behold God's holiness, we desire to be like him. Yet we also perceive how unworthy we are, and these two are inextricable: we must either see that God is good and we are not, or we will believe that we are good and judge God, not that we can judge God, but we will either hold him to our standard or see that we fall short of his standard.
Then, as we see God's holiness and our unholiness, we will see how great the wrath we deserve, and so how great a salvation we have in Jesus Christ our Lord. Without God's wrath, there is no sanctification, no justification, because without God's wrath there is no need for it. Yet there is a great need in us to be reconciled with God, for we were rebels against him. God's wrath means that sin must be dealt with. Yet we are unable to deal with our sin, and so we need Jesus Christ to deal with it for us.
And this is why, when Paul imagines someone suggesting that we sin all the more that grace may abound, he responds with "By no means!" For our God hates sin, and it is this hatred which is the root of our salvation from sin. It was in recognition of God's wrath against us in our sin that we saw our need for a savior. It was in recognition of our low state that we clung to Christ, and it is by his life which we are renewed to live as he lived. We are changed so as to hate our sin, as we behold our salvation from it. Because we are no longer held guilty for our sins, and because we recognize it to deserve God's wrath, we are freed from our sins. The power of sin can no longer compel us to sin, but the power of Jesus Christ now compels us to good works.
The wrath of God is important for the bigness of God. It means that he is our judge, our Lord. He is the judge, the standard of all goodness. He is not passive as the standard of all goodness, but active and vigorous. He does not merely stand by as the measure of what is good, he executes justice against all ungodliness. This means that we have hope that he will make all things right in the last day. He is mighty and powerful to work righteousness, not as we would have him do it, but in his good and perfect way, in the fulness of time, to bring glory to himself. We look forward to that day, when all the evils will be judged, and all righteousness rewarded. In that day God's wrath will be shown clearly and we will glorify him for hi justice and goodness and behold the fulness of his mercy and grace to us, as he passes over us for the sake of the lamb who was slain.