At the Heart of the Christian Gospel

“The gospel tells us that our Creator has become our Redeemer. It announces that the Son of God has become man and has died on the cross to save us from eternal judgment. The basic description of the saving death of Christ in the Bible is as a propitiation, that is, as that which quenched God’s wrath against us by obliterating our sins from his sight. God’s wrath is his righteousness reacting against unrighteousness; it shows itself in retributive justice. But Jesus Christ has shielded us from the nightmare prospect of retributive justice by becoming our representative substitute, in obedience to his Father’s will, and receiving the wages of our sin in our place.
By this means justice has been done, for the sins of all that will ever be pardoned were judged and punished in the person of God the Son, and it is on this basis that pardon is now offered to us offenders. Redeeming love and retributive justice joined hands, so to speak, at Calvary, for there God showed himself to be ‘just, and the justifier of him that hath faith in Jesus.’
Do you understand this? If you do, you are now seeing to the very heart of the Christian gospel. No version of that message goes deeper than that which declares man’s root problem before God to be his sin, which evokes wrath, and God’s basic provision for man to be propitiation, which out of wrath brings peace. Some versions of the gospel, indeed, are open to blame because they never get down to this level.” - Dr. J. I. Packer