Why the Doctrine of the Trinity Matters

First, the Doctrine of the Trinity in a nutshell: There is just one true God, and his name is the Lord (YHWH). The Lord is one God in three Persons - the Father, the Son, and the Holy Spirit. The Father is fully God; the Son is fully God; the Holy Spirit is fully God.

Since this Sunday is "Holy Trinity Sunday" in many churches, it seems good to consider why the Doctrine of the Trinity matters. Three reasons immediately come to mind (feel free to add your own in the comments):

1. Because God is Love

Frequently quoted is 1^st John 4:16: “God is love.” Less frequent is the recognition that this statement could not be true without the Doctrine of the Trinity. How so? Briefly put, in order for God to be love, there must first be someone or something for Him to love. There can be no love without a beloved.

Before He created the world, who or what was there for God to love? That is, who or what was God’s beloved? The Doctrine of the Trinity answers: The Father has loved the Son for all eternity, the Son has loved the Father for all eternity, and the Holy Spirit is the eternal bond of love between them. God is - always has been, and always will be - love.

If God were not triune, then love would not be his eternal nature. But since He is triune, it can be said without reservation or logical contradiction: God is love. And why does that matter? Because this divine Fellowship of Love is the fellowship into which a Christian is baptized – “in the Name of the Father and of the Son and of the Holy Spirit” – meaning the truly Christian life is the one lived in God's everlasting love.

2. Because Denying Divinity Has Logical Consequences

If Jesus Christ is not God, then those who believe in Him are not saved. Why? Because only God can save. No mere man can overcome the unholy trinity of sin, death, and the devil. Jesus Christ is not merely a man. He is God, and that means He can save.

Likewise, if the Holy Spirit is not God, then we are not saved. (Again, only God can save.) If, in having the Holy Spirit, we do not have God himself, then we are still separated from God. However, because the Holy Spirit is God, having Him inside is having God inside. It can be said that the Spirit is salvation Himself, living within.

Frequently the New Testament admonishes us to entrust our lives to Jesus and to receive the Holy Spirit as our guarantor of salvation. If Jesus were not God, and if the Holy Spirit were not God, this would be foolish advice. However, the lived experience of many Christians is that entrusting one’s life to Jesus and receiving the Holy Spirit brings salvation. Is this not a sign that Jesus and the Spirit are indeed God?

3. Because It’s True

Maybe this is obvious, but it should be stated nonetheless. The Doctrine of the Trinity matters because it is true. Perhaps this is offensive to those with post-modern sensibilities, but truth matters. It has consequences for how we live, and living contrary to the truth never works.

To use a mundane example, someone looking for a tropical vacation would be foolish to book a flight to Antarctica. Antarctica might be a very lovely place, but the truth is that it won’t provide much in the way of balmy weather and drinks on the beach.

Just so, someone looking for God would be foolish to look for Him outside of Christ Jesus and outside of his Holy Spirit. The truth is that God has revealed Himself as the Father, Son, and Holy Spirit. One whose desire is for God (and truly, everyone’s ultimate desire is for God) should be told to cling to Christ Jesus, and to receive and live by the Holy Spirit. Only then will God be found and the human heart satisfied.