What Does ‘Trinitarian’ Mean in Christianity?

Clarence L. Haynes Jr. Contributing Writer
Updated Jan 31, 2022

One of the things that separates Christianity from every other religion in the world is our belief in the Trinity. People who hold this belief are often referred to as Trinitarians.

What Does Trinitarian Mean?

What "trinitarian" means in Christianity is there is one God who has been revealed in three persons. We know them as God the Father, God the Son, and God the Holy Spirit.

It is safe to say that of all the doctrines within Christianity, this is probably one of the most controversial or difficult ones to comprehend – especially for those outside the faith. But it doesn’t stop there because people inside the faith can often wrestle with this truth that is so essential to Christian doctrine. My objective is not to prove to you from the Bible why this is true, which I would be more than happy to do in another article. My desire is to help you understand what trinitarian means to Christianity, something it reveals about you, and why it is so important.

All of Christianity Hinges on Trinitarian Doctrine

I don’t know if you have ever thought about this or not but the essence of your Christian faith hinges on this truth. The center of the Christian faith is Jesus Christ. That he would come and surrender his life to be the perfect atoning sacrifice for our sin. What makes this so essential is that Jesus was not just an ordinary man, but he was God in flesh, conceived by the power of the Holy Spirit and born through the virgin Mary. When he walked the earth, he was not just the son of Joseph and Mary, he was the Son of God. In him, he carried full humanity and full divinity. That idea alone is something that people struggle to understand but it sits at the heart of the trinitarian doctrine and is fundamental to the Christian faith. If Jesus is not God, then the message of Christianity crumbles, because Jesus is the foundation of it all. That’s why the entire Christian faith rests on this truth of who Jesus is and why Satan works so hard to blind people to this reality. Once you know who Jesus is not only does that open the door to salvation it sheds light on the doctrine of the trinity because you begin to see God revealing who he is.

The Bible Is Clear That There Is Only One God

One thing the Bible is very clear about is that there is only one God.

This is what the Lord says— Israel’s King and Redeemer, the Lord Almighty: I am the first and I am the last; apart from me there is no God. – Isaiah 44:6

Hear, O Israel: The Lord our God, the Lord is one. – Deuteronomy 6:4

Most people will not question that and find the idea of one God to be quite acceptable, reasonable, and easy to understand. When you go beyond that is when the questions and supposed controversies arise. For people who stand against the idea of the trinity, they believe that we are trying to say that there are really three Gods, not one. However, what is woven through the pages of scripture is this truth of God revealing himself as one God in three persons.

One of the arguments people make against the doctrine of the trinity is that it doesn’t make sense and since it can’t be reasoned then it must not be true. The question that you must ask yourself is do you define God by your reason and what is reasonable to you, or do you define God by how he has chosen to reveal himself? If you go by your reason, then God is limited to your capacity to understand. If you go by his revelation, then you are not required to figure every aspect of God out because the truth is you can’t do it anyway. This does not mean we cannot understand him at least partially, but it does mean that his understanding also goes beyond our comprehension, and you cannot let that hinder, dimmish, or limit who he is. Remember he is an infinite God and the best we can do is try to gain an understanding of who he is with our finite minds. Consider these words from the book of Job.

Look, God is greater than we can understand. His years cannot be counted (Job 36:26 NLT).

One Simple Reason That Makes the Trinitarian Doctrine Possible

One reason why you can begin to accept trinitarian doctrine is that nothing is impossible with God. To say that the doctrine of the trinity cannot be true is to say that God cannot be revealed in this manner. That he cannot be one God revealed in three persons. If you are going to approach trinitarian belief and approach God, you must recognize that he is the God of the impossible. Not only are his ways higher than ours but everything he does is higher than ours. We must be careful not to put God in a nice, neat little box where we can explain everything about him. The truth is whatever you think or understand about God, it is greater than you think. His love is greater than you think. His mercy is greater than you think. His power is greater than you think. God’s triune nature fits in line with who he is because he is greater. The moment you think you have got God all figured out then at that moment he stops being God.

To say that God cannot be revealed in three persons because that doesn’t make sense to the human mind limits God to your ability to understand, which means you have brought God down to your level. If God is only God to the extent of your human reasoning, then this is another instance where he stops being God. In Ephesians 3:20, we are reminded that God is able to do exceedingly and abundantly more than we could even imagine. This means that God’s character sits outside of our ability to completely understand it, but just because you don’t have a complete understanding of who God is, does not make the revelation of who he is untrue, nor does it make it not possible.

One Question That Defines How You Respond to the Trinitarian Doctrine

Ultimately what trinitarian means to Christianity really comes down to one question. Do you trust what God has revealed about himself in his word? This really is the question that matters, and it points to how much weight and trust you put in the word of God. The Bible is very clear about how God is defined, and it leaves no doubt about who God is. The triune nature of God is evident throughout the pages of scripture and God has clearly chosen to reveal himself as God the Father, God the Son, and God the Holy Spirit or one God in three persons. If you trust the validity of scripture, then you will trust the trinitarian doctrine because you cannot deny its presence in the Bible. If you don’t trust the validity of scripture, then you will not hold onto the doctrine of the trinity because the foundation of this doctrine comes from the word of God. What it comes down to is will you trust what God has said or will you trust something else? Whatever side of this question you fall on will define what you believe about who God is and it will also define how you align with his word. I would encourage you, if you are not sure of what the Bible says on this topic, then become sure. Take whatever time is necessary to be certain of this doctrine because understanding this truth means everything to your Christian faith.

Quotes by Scholars about Trinitarian Doctrine

"The three persons of the Trinity, Father, Son, and Holy Ghost, consult about it and concur in it, because man, when he was made, was to be dedicated and devoted to Father, Son and Holy Ghost. Into that great name we are, with good reason, baptized, for to that great name we owe our being."

- Excerpted from Matthew Henry's Commentary on Genesis 1

The doctrine of the Trinity is revealed in the Old Testament, in the same degree that the other truths of Christianity are; not with the clearness and fulness of the New Testament, yet really and plainly. God is trinal in the Old Testament; but with more vagueness than in the New. In the Old economy, only the general doctrine of three persons in the essence is taught. In the New dispensation, the characteristic differences between the three are specified.

Excerpted from Dogmatic Theology, Theology (Doctrine of God), Chapter IV by William Greenough Thayer Shedd