For five hundred years, Christians in the lineage of the Reformation — that is, Protestant Christians who love the Bible and are bent on seeing the gospel for all that it is — have described the gospel in terms of five solas, which is the Latin word for only or alone — like the English word solo.
What I want to do is just put those five together in a gospel definition and add one, which is implicit in the other five. You can decide if it’s eccentric or not: As revealed with final authority in Scripture alone, the gospel is the good news that by faith alone, through grace alone, on the basis of Christ alone, for the glory of God alone, sinners are granted to enjoy God alone forever. Enjoying God alone is my own addition, but Calvin, Luther, Zwingli, the Puritans, Jonathan Edwards, Spurgeon — all this long line of Reformation lovers of the gospel would hear me say that and respond, Amen. Let me show you how biblical these are.
1. Scripture alone is the final authority in defining the gospel. Galatians 1:9: “If anyone is preaching to you a gospel contrary to the one you received, let him be accursed.” That’s a big claim. In other words, the gospel is decisively and finally controlled by the apostolic delivery. If anybody comes along with something to change it or add to it, don’t pay any attention. So Scripture alone is the defining authority for the gospel — not any later church authority.
2. The gospel comes to us by faith alone. Romans 3:28: “We hold that one is justified by faith apart from works of the law.” So faith plus nothing that you do is how you receive the gift of the gospel, the gift of justification, the gift of freedom from wrath, that gift of enjoying God.
3. The gospel comes to us by grace alone. Ephesians 2:5: “When we were dead in our trespasses, [God] made us alive together with Christ — by grace.” By grace, you have been saved when you were dead and couldn’t do anything. It’s totally grace. Ephesians 2:8: “For by grace you have been saved through faith. And this is not your own doing.” Grace alone.
4. The gospel comes to us on the basis of Christ alone. There’s no other basis. Hebrews 7:27: “[Christ] has no need, like those high priests [of the Old Testament], to offer sacrifices daily, first for his own sins and then for those of the people, since he did this once for all when he offered up himself.” You can’t add anything to it, not even one millisecond after it’s done. Once for all, the price is paid: Christ alone, foundation for your deliverance, your forgiveness, your justification, your freedom from wrath — one basis. And it’s not in you.
I remember in seminary when I first heard the phrase extra nos. Your salvation is extra nos — outside of you. You know people are so worked up about me. “I’m a believer. Am I doing this? Am I doing that? Am I doing this?” Stop thinking about yourself for a minute. Dwell on these glories outside of you. God did something in Christ spectacularly. He’s the only foundation.
5. The gospel is for the glory of God alone. Ephesians 1:5–6: “[God] predestined us for adoption to himself as sons through Jesus Christ, according to the purpose of his will, to the praise of his glorious grace.” He did it in such a way that there will be no human boasting before God. There will only be praise of his initiative in his glory.
6. The gospel brings full and final joy in God alone. This is where it’s all going. Psalm 16:11: “In your presence there is fullness of joy; at your right hand are pleasures forevermore.” Psalm 73:25–26: “Whom have I in heaven but you? And there is nothing on earth that I desire besides you. My flesh and my heart may fail, but God is the strength of my heart and my portion forever.”
That’s where the gospel is going: for the enjoyment of God — nothing less and nothing beyond. He is the prize of the solas.
Source: John Piper | Desiring God