Despite our best efforts to simplify things, Christianity is not a math equation. The Bible cannot be reduced to a series of principles or ideas which can be plugged and chugged to equal salvation like a heavenly quadratic formula. As the New Testament repeatedly reminds us, even the simple commands of Scripture are much deeper than they first appear. When the rich young man triumphantly tells Jesus that he has kept the commandments from the law, “Jesus, looking at him, loved him, and said to him, ‘You lack one thing: go, sell all that you have and give to the poor, and you will have treasure in heaven; and come, follow me.’” (Mark 10:21) Christianity is not a problem to solve, but a person to follow. Therefore, the Gospel, or the good news of the Bible, is that God saves sinners not because of what we do or have done, but because of what Jesus Christ has done on the cross to pay for our sins.
In this sense, the most important doctrine in the Bible is the Gospel. When the Philippian jailer asks Paul and Silas what he must do to be saved, their answer is simple: “Believe in the Lord Jesus, and you will be saved.” (Acts 16:30-31) Unfortunately, in many churches today, Christians think that this is the last question a sinner should ever ask, as if salvation itself is the most ultimate goal of Christianity. But it’s not. Apathetic churchgoers, often trying to reduce Christianity to a math equation, can assume that their journey ends with a particular prayer or an act of baptism. But these things are only the beginning. When we’re saved, we’re saved to something. To someone. Therefore, justification by faith isn’t the most foundational doctrine of Christianity. And neither is the rebirth. Both of these things are accomplished by the God who is the beginning and end of all things. (Rom. 11: 36) In other words, God is the point. After God saved Moses and the Israelites from Egyptian slavery and gave them his law, Moses wanted more. He had another request: “Please show me your glory.” (Exodus 33:18) Moses didn’t just want salvation from God. He wanted God.
Running beneath the doctrine of creation and atonement and the new birth is the most foundational doctrine in Christianity, something which many churches unfortunately treat as abstract or unimportant: the doctrine of the triune God. The Trinity. The God of Three Persons breathes meaning and purpose into every single command, idea, and doctrine of the Bible. Including our prayers to the Father in the name of the Son. (2 Cor. 1:20) Including our baptisms in the name of the Father, Son, and Holy Spirit. (Matt. 28:19-20) And when we glory in the Trinity, the Bible comes alive. The Father creates. The Son saves. The Spirit sanctifies. The beauty of the Gospel comes into view when we see each person of the Triune God working for our good. The Father gives the Son to receive the wrath of the Father in our place. (1 John 2:2) The Son sends the Spirit so that we can be children of the Father. (Rom. 8:15) For Jesus, salvation wasn’t about formulas, but about inviting sinners to participate in the inner life and unity of the Triune God. (John 17:22-24) A Christian is actually united to Christ and indwelled by the Spirit! The Trinity is the ground and goal of our salvation. Without the Trinity, Christianity has no grand story to tell. Without the Trinity, our faith becomes less about God’s rescue plan and more about a self-centered math problem: faith + Jesus = heaven. But that equation doesn’t add up. Heaven isn’t the prize. The triune God is.
The Gospel is about salvation. And salvation is about Jesus. And Jesus is the second Person of the God who redeems His church that he might display His full Trinitarian splendor! God wants to reveal Himself to His church, and He does so through the Gospel. When a church dismisses the doctrine of the Trinity and makes salvation the most ultimate end of Christianity, it loses its worship of God for God’s sake. It prioritizes gifts over God. But Christianity isn’t about us. It’s about the Savior, fully man and fully God. When we preach the saving Gospel of Jesus Christ, we save people to God and from themselves, not from God and to themselves. Therefore, the Trinity isn’t an abstract doctrine. He’s the reason for our praise.