The good news that constitutes what we call the Christian “gospel” is nowhere better summarized than in 1 Peter 3:18. There the apostle tells us that “Christ also suffered once for sins, the righteous for the unrighteous, that he might bring us to God.”
There is so much worthy of our consideration in this text, but I want to draw your attention to only one word: “for”. Jesus, who was perfectly and altogether righteous, suffered FOR you and me, we who are profoundly unrighteous.
Peter’s point is that when Jesus suffered for sins it was in the place of sinners: it was for them, as a substitute.
We speak often of the sacrifice of Christ as substitutionary. Jesus didn’t simply love us from a distance. He didn’t merely speak of his mercy or his grace. That would have been of no benefit to us. What we needed first and foremost and above all else was the sinless Son of God to become one of us, a human being, and as the God-man to live a life for us that we could not live, in complete and perfect obedience to the law of God, and to die a death that we should have died to satisfy the wrath of God that we alone deserved.
This is what Peter means when he speaks of Jesus suffering “for” us, in our place, enduring what we deserved, dying our death.
If Jesus did not die as your substitute, filling your place, standing in your stead, taking upon himself the obligation and debt that you owed God, then you must face the wrath of God, for yourself, on your own, all alone. Do you not see, then, that if there is no substitution there is no salvation? Do you not see, then, how eternally important that little word “for” is?
In the absence of what the preposition “for” tells us about the death of Jesus, we have no hope. Delete what “for” implies and we have no gospel, no good news to share with a dying world. No other preposition conveys what “for” does. Not “to” or “with” or “beside” or “through” or “behind” or “about” or “in” or “on” or any other preposition conveys the notion that when Jesus the righteous suffered because of the sins of the unrighteous, he did it “for” them, which is to say, in their place, standing in their stead, enduring the judgment that they deserved, all so that he might by means of this death and subsequent resurrection, bring us to God.
That is the gospel: God, through the life, death, and resurrection of Jesus, graciously doing everything necessary to get us to him! Oh, what a glorious gospel it is!