Question: I’ve heard the word “trinity” used a lot, but I don’t quite understand what it is and why it is so important for Christians. Can you explain?
Thanks for asking! You are correct, the doctrine of the trinity is a very important doctrine of the Christian faith. It is unique in that the word “trinity” is never actually given in the Bible. However, the idea of the trinity is given throughout Scripture.
First, what IS the trinity? In his book Systematic Theology, Wayne Grudem defines the trinity in this way: “God eternally exists as three persons, Father, Son, and Holy Spirit, and each person is fully God, and there is one God.”
To understand what this means, he gives three key statements that summarize the biblical teaching of the trinity. These statements are: 1) God is three persons, 2) Each person is fully God, 3) There is one God. Each of these are clearly supported by a ton of New Testament and Old Testament passages. I will only give examples here, but feel free to look at chapter 14 of the book for a more detailed look.
1) God is three persons
There are three distinct persons of God: the Father, Son, and Holy Spirit. John 1:1 distinguishes between the Father and the Son. “In the beginning was the Word [Jesus], and the Word was with God, and the Word was God.” In John 14:26, we see the distinction between the Father, Son, and the Holy Spirit. Jesus says, “But the Helper, the Holy Spirit, whom the Father will send in my name, he will teach you all things and bring to your remembrance all that I have said to you”
The key here is that there are three distinct persons. Not different forms of the same person. Not different personalities of the same person. Not two persons. Three distinct persons.
2) Each person is fully God
Each of these three distinct persons are FULLY God. One is not more God than the other. All three are fully God. Listen to these two passages that put the three persons at the same level. In Matthew 28:19, Jesus says to baptize people “in the name of the Father and of the Son and of the Holy Spirit.” And in 1 Corinthians 12:4-6, Paul says, “Now there are varieties of gifts, but the same Spirit; and there are varieties of service, but the same Lord; and there are varieties of activities, but it is the same God who empowers them all in everyone.” Notice the reference to all three: the Spirit, the Lord (Jesus), and God (Father).
God the Father is usually seen as fully God, but what about the other two? John 1:2-4 says of Jesus, “He was in the beginning with God. All things were made through him, and without him was not any thing made that was made. In him was life, and the life was the light of men.” Near the end of John, it says, “Now Jesus did many other signs in the presence of the disciples, which are not written in this book; but these are written so that you may believe that Jesus is the Christ, the Son of God, and that by believing you may have life in his name” (John 20:30–31). Jesus was not just a good prophet or teacher, he was and is God.
Then speaking of the Spirit, In Acts 5:3–4, Peter asks Ananias, “Why has Satan filled your heart to lie to the Holy Spirit . . .? You have not lied to man but to God.” Notice he is saying that the Holy Spirit is God.
3) There is one God
The idea that there is only one God is clearly stated in Scripture. It says in Deuteronomy 6:4-5, “Hear, O Israel: The Lord our God, the Lord is one. You shall love the Lord your God with all your heart and with all your soul and with all your might.” In Isaiah 45:5, God says, “I am the LORD, and there is no other, besides me there is no God;”
This same idea is stated in the New Testament. For example, Paul writes in 1 Timothy 2:5, “For there is one God…”
Now let’s be honest for a moment. Does this make sense to our human brains? No! How can there be three distinct persons, yet only one God? The reality is that, to an extent, this will always be a mystery to us. That’s where faith comes into play. We won’t understand everything. That’s OK. But we can still have faith in him even if we don’t understand every aspect.
Why is this important?
So why is it so important to get these three points about the trinity? Since these three statements are clearly given in Scripture, denying any part of these three statements will lead us down a path of incorrectly following God or other aspects of the Christian faith.
At various times throughout history, people have held to something called “modalism.” This is the belief that God is not really three distinct persons, but the same person in three forms. However, to believe this is to deny the power of John 3:16, where God sent his son to save us. It messes with the doctrine of the atonement, that Jesus came and died for us. In short, you mess with “three persons” and you begin walking into some very muddy water. This belief is presently held by the United Pentecostal Church.
Another faulty belief is called “Arianism.” This is the belief that God the Father created God the Son. However, to believe that Jesus was created completely corrupts the entire New Testament message that Jesus, as God, was the perfect substitute for our sins. Mormons, Jehovah Witnesses, and some unitarians all hold to this teaching.
Simply put, if you err on the basic teachings of the trinity, you are in danger of drifting away from foundational teachings about the Christian faith. So not only is the doctrine of the trinity an important doctrine because it is true, but it is important because it helps us better understand Christianity as a whole.