How to Explain the Trinity in 4 Steps

So you’d like to know how to explain the Trinity? 

Easy.

Well, actually no. The Most Holy Trinity is the central mystery of the Christian faith… you can’t expect it to be easy, right? 

But don’t worry, I’m going to break down four trinitarian principles that will make it much easier for you to both understand and explain the mystery of the Most Holy Trinity.

How to Explain the Trinity as a Mystery of Faith

However, first we must make sense of what the Catholic Church means when it refers to the Trinity as a mystery. 

At the First Vatican Council the Church provided us with the following Christian understanding of the term mystery:

“[M]ysteries hidden in God are proposed to us for belief which, had they not been divinely revealed, could not become known” (Dei Filius 4).

In other words, divine mysteries are truths hidden in God that are inaccessible to the operation of our reason alone and, therefore, only knowable due to God’s free decision to reveal them to us. 

To say that divine mysteries, such as the Most Holy Trinity, are inaccessible to the operation of our reason alone is not to say that these mysteries are unreasonable. No. Rather, divine mysteries are very reasonable. They must be. They find their origin in God, the very source of all reason. 

Even so, we come to know divine mysteries by faith and not reason. And this is why the Church calls them mysteries of faith. 

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Lastly, it should also be noted that since these mysteries of faith are truths dealing with God, an almighty and infinite being, no matter how hard or long we try to contemplate these mysteries in our lifetime we will always be unable to grasp them in their entirety. 

As St. Augustine famously said, “If you understood Him, it would not be God” (Sermon 52, 6, 16: PL 38, 360 and Sermon 117, 3, 5: PL 38, 663). God is beyond the entire universe and our brains are just a small part of the universe. There is no way we can fit God into our minds and that is OK. Again, if we could it wouldn’t be God. 

Let’s now turn and look at the four trinitarian principles that will help you to better understand and explain the Trinity.

How To Explain the Trinity Using Four Trinitarian Principles

As we break down the following four trinitarian principles, be aware that this is not an exhaustive explanation of the Trinity nor are these principles the only principles of the Trinity. This breakdown is merely meant to assist you in your own understanding of the mystery of the Most Holy Trinity and sharpen your ability to explain it to others. 

That said, you can be sure that God contains perfectly within Himself, at all times, all four of these trinitarian principles: 

Principle #1: Unity

First and foremost, it can not be reiterated enough: We, Christians, believe in only one God. 

And we believe that there is perfect unity within the one God. 

Be reminded of the words with which the Nicene Creed begins: “I believe in one God, the Father almighty, maker of heaven and earth, of all things visible and invisible …”

In addition, the Roman Catechism from the Council of Trent couldn’t be any more clear: “The Christian faith confesses that God is one in nature, substance, and essence” (Roman Catechism I, 2, 2). 

This truth that there is only one God and that God is one is rooted in God’s revelation in the Old Covenant, when God revealed Himself to Israel as the only God:

“Hear, O Israel: The LORD our God is one LORD; and you shall love the LORD your God with all your heart, and with all your soul, and with all your might” (Deuteronomy 6:4-5). 

“Turn to me and be saved, all the ends of the earth! For I am God, and there is no other… To me every knee shall bow, every tongue shall swear” (Isaiah 45:22-23).

Therefore, before moving on to consider the three persons of the Trinity it must be affirmed with all sincerity that God is one. 

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Principle #2: Distinction

OK, so if God is one how could there possibly be distinction within God? 

Well, first remember, what we are contemplating here is a divine mystery. And so, though we can say and understand something about the inner life of God we can’t say and understand everything. Let alone much.

And so let’s do our best, within the limits of human language, to make sense of how distinction exists within the life of God.

So what sort of distinction are we talking about?

It can be said that while remaining perfectly one there is a distinction of persons within the inner life of God. Though the term person (hypostasis) doesn’t totally grasp at the reality of the persons of the Trinity, it does give us something to say when describing the distinction between the Father, Son, and Holy Spirit. 

And it’s important to note that a person is not something but someone. And as someone, a person has the capacity for love—for being in relationship with another. 

It is because of this understanding of what it means to be a person, in reflection of St. John the Apostle’s statement in his letter that “God is love” (1 John 4:16), that the Most Holy Trinity is often described as a communion of love—that between the Father, Son, and Holy Spirit we have the drama of love between a Lover (Father), His Beloved (Son), and their shared Love (Holy Spirit). 

In addition to this image of love, to properly understand this distinction of persons between the Father, Son, and Holy Spirit, the following needs to be said:

The Father is not the Son. The Son is not the Holy Spirit. And the Holy Spirit is not the Father. 

However, the Father is God. The Son is God, And the Holy Spirit is God. 

And they are not three Gods, but one God. 

True distinction, yet true unity.

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Principle #3: Order

To further our understanding of the distinction of persons within the one God it is best to move on to the next trinitarian principle.

Among the three persons of the Trinity, there is a proper order:

1. The Father is the First Person of the Most Holy Trinity.

2. The Son is the Second Person of the Most Holy Trinity.

3. The Holy Spirit is the Third Person of the Most Holy Trinity.

This order does not come about by their ranking of power, but rather by their relation of origin.

Though all three have always existed (as God), the distinction between the three persons lies in the relation of origin they have among each other.

The Father is related to the Son as the one who generates the Son eternally as his Word. The Son is related to the Father as the one originating from the Father eternally. The Spirit is related to the Father and the Son as he originates eternally from the Father and the Son as their spirated (or breathed) love. 

Therefore, in regards to order, it can be said that the Father is the person who is the origin of trinitarian life, who eternally generates the Son and spirates the Holy Spirit. He communicates the whole life of God to the Son and to the Holy Spirit so that they possess all that the Father has. 

The Son (and Word) is He who is eternally generated by the Father and proceeds from Him and who, with the Father, spirates the Holy Spirit.

The Holy Spirit is the eternal person who is subsistent love, spirated forth from the Father and the Son.

Though it is true that this order within the life of God comes about by the relation of origin among the persons of the Trinity, it can also be seen that this order within God is an expression of the inner drama of love:

It is the Father (Lover) who sees the perfection of His Word/Son (Beloved) and can’t help it but love His Word/Son totally and eternally. And, as a result, the Father and the Word/Son share in this great sigh, or breath, of love, which is the Holy Spirit. The love between the Father and the Word/Son is so profound that it goes beyond them and bears fruit in the Holy Spirit, much like how the love between a husband and wife goes beyond them and bears fruit in a third person, their child. 

Therefore, the order of the persons of the Most Holy Trinity is not arbitrary but, instead, reveals the genuine order that exists within the inner life of God.  

Principle #4: Equality

If there is a proper order of persons within God then how could there be equality? From human experience, when there is a first, second, and third there is not usually equality. 

Again, this is where I remind you that God is beyond this universe. That you will not find anything in the created order that perfectly integrates all four of these principles. But God, as Trinity, does. 

So, how can we make sense of perfect order and equality within the life of God then?

Let me draw on a helpful analogy…

Within a family, you have a husband/father, a wife/mother, and a child (or children). When sin is not the rule, both order and equality not only exist but can flourish. 

The husband/father is first, the wife/mother is second, and the child is third. Why? Because, unless the husband actively gives of himself to his wife it is impossible for the wife to actively give of herself to the child. For the human family to flourish and beget life effectively it must follow this proper order of being (for strong evidence of this just look at the opposite approach of modern society). 

However, this order within the family (when sin is not at play) is not a cause for inequality. In fact, most wholesome families recognize the equality of each of its members. 

Regardless of one’s experience, however, a husband is not greater than his wife, and a father and mother are not greater than their child. And when a family is properly ordered according to God’s design, it is that very order which fosters equality within the life of the family.

All of this to show that it is possible for both order and equality to exist together. And I believe the human family, according to God’s design, gives us a glimpse into the order and equality that exists within the life of the Most Holy Trinity. 

And so, in addition to the true order among the persons of the Trinity, there is also perfect equality:

The Father is not more God than the Son. And the Father and the Son are not more God than the Holy Spirit. 

The Father, Son, and Holy Spirit have always existed as one God outside of time and space. 

But the Father is first, the Son is second, and the Holy Spirit is third.

Trinitarian Heresies

There are three heresies (or errors) that have been popular over the course of Church history that when reviewed in light of these four trinitarian principles can help us to think more clearly about the mystery of the Most Holy Trinity:

#1 Modalism

Modalism is the view that there is only one person in God, but that this one person manifests himself in three different ways or modes: as creator (Father), redeemer (Son), and sanctifier (Holy Spirit). Modalism accepts the principle of Unity while denying the principle of distinction.

#2 Subordinationism 

​​Subordinationism asserts that the Son and the Holy Spirit are subordinate to God the Father ontologically (in terms of nature and being). Subordinationism accepts the principle of Order while denying the principle of Equality.

#3 Tri-theism

Tri-theism divides the substance of the Blessed Trinity, giving each divine person a nature that is numerically distinct from the nature of both the other persons. Tri-theism accepts the principle of distinction while denying the principle of unity.

With these three trinitarian heresies in mind, you can consider that a proper understanding of the Trinity is somewhere right in the middle of all three heresies, keeping a true integration of all four trinitarian principles of Unity, Distinction, Order, and Equality. 

RELATED: The Magisterium of the Catholic Church (& why it’s so important)

Does the Trinity Matter?

So you’re killing it, confidently explaining each of the four trinitarian principles to your friend and they’re totally getting it. But then…

They ask you: “So… why does this even matter?”

***blank stare***

Yikes. You don’t want this to happen to you do you?

So, let’s answer the question: Why does the mystery of the Most Holy Trinity matter?

I mean it has to, right? God became man to reveal it to us and, as I stated earlier, it’s only the central mystery of the entire Christian faith. 

Don’t worry. It matters. And I’ll give you two reasons why…

First, our image of God determines the image we have of ourselves and how we choose to live our lives. 

For instance, if we believe God to be a distant God that merely created the universe and then left it to itself with no further care or interaction, then we are likely to live our own lives with very little care for God and His Law. 

Or, if we believe God to be a violent God, one who exerts arbitrary power over His creation just for the sake of subjugating all beneath Him, then we, as His creatures, are likely to rebel (rightfully so) against God. All of life would be seen as a power struggle, between God and humanity, between human beings among themselves, and even between humanity and all other creatures. Sound familiar?

Or lastly, if we believe God to be a triune communion of love, who freely pours Himself forth so that others might share in His Life, then we might have a much different response to God and view of how we should live our lives. We may even see love as the ultimate theme of our existence. 

RELATED: The Prayers I Pray Every Morning (to the Most Holy Trinity)

See, the fact that God is triune matters. 

Therefore, I invite you to consider: If the principles of unity, distinction, order, and equality all truly exist within God, how does this affect our lives as human beings?

Second, if God is truly our loving Father, as Jesus reveals in the Gospels, then we are made for an intimate and loving relationship with God. Who doesn’t want to better understand and know the inner workings of their beloved?

The truth is that we exist for loving communion with God. We exist to participate in the inner life of the Most Holy Trinity—to be caught up in the life and love of God. 

And because of this truth, there is no more worthy human act than contemplation of the Most Holy Trinity. Just as a man longs to contemplate the reality of his beloved and have intimacy with her, not for any practical reason but merely because he loves her and is captivated by her mystery, so should we long to contemplate the mystery of God and desire intimacy with Him. 

Therefore, the Trinity matters. Not even just for practical reasons. But because “it is the mystery of God in himself” (Catechism of the Catholic Church 234). And God is a mystery worth contemplating.

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Do you feel more confident in your ability to explain the Trinity? Why or why not?

Let me know below in the comment box!