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By Michael Terheyden

5/25/2013 (3 years ago)

Catholic Online (

Imagine what it is like for God to know Himself and love Himself. Since God is infinite, His knowledge of Himself and His love of Himself must also be infinite and perfect in every detail. This is the key to making sense of the Trinity.

The Most Holy Trinity

The Most Holy Trinity


By Michael Terheyden

Catholic Online (

5/25/2013 (3 years ago)

Published in Year of Faith

Keywords: Trinity, Father, Son, Holy Spirit, Catholic, Church, Michael Terheyden

KNOXVILLE, TN (Catholic Online) - According to the Catechism of the Catholic Church, "The mystery of the Most Holy Trinity is the central mystery of Christian faith and life" (234). One reason the Trinity is so mysterious to us is because it seems like a contradiction. However, one of the few things we can know about the Trinity is that it is not a contradiction. We can make some sense of it.

In his book, Theology and Sanity, Catholic apologist Frank Sheed explains how God can be one in being yet three persons. Sheed's explanation is one of the most clear and helpful explanations I have ever read. I have tried to simplify it and condense it for you in this article. However, I can only offer you a preview, so to speak, but I hope it inspires you to learn more about the Trinity in the future. 

The key to making sense of the Trinity is based on the relationship between infinity and existence. To understand infinity, imagine a being who did not receive existence from another source, but is existence itself. Since this being is existence, it cannot be limited in any way. Therefore, it must be infinite, that is, having the fullness of existence. And because only one being can be the fullness of existence, we know that this being is God.

Now, imagine what it is like for God to know Himself and love Himself. Since God is infinite, His knowledge of Himself and His love of Himself must also be infinite and perfect in every detail. This means that within His own nature God is what He knows and what He loves. This is the key to making sense of the Trinity.

What does it mean to say that God is what He knows? It means that God is His idea of Himself. As an infinite being, God's idea of Himself lacks nothing of who He is. The idea that God generates of Himself, which is the whole of His Divine Nature and equal to Himself, is another person. In other words, "The First Person knows Himself; His act of knowing Himself produces an Idea, a Word; and this Idea, this Word, the perfect Image of Himself, is the Second Person."

Thus, we have a distinction between the Father and the Son. Having said this, we must be careful not to think that the Father is before the Son. Since God is existence and infinite, He is not limited to space and time. God is eternal. This means that He did not become a father and son, He was always Father and Son.

Having touched on the relationship between the Father and the Son, we can move on to the Third Person in the Trinity. What does it mean to say that God is what He loves? Frank Sheed answers this question, and in doing so, offers us a beautiful explanation of the Holy Spirit in relation to the Father and the Son.

"The First Person and the Second combine in an act of love--love of one another, love of the glory of the Godhead which is their own; and just as the act of knowing produces an Idea within the Divine Nature, the act of loving produces a state of Lovingness within the Divine Nature. Into this Lovingness, Father and Son pour all that they have and all that they are, with no diminution, nothing held back. Thus, the Lovingness within the Godhead is utterly equal to the Father and the Son, for they have poured their all into it. There is nothing they have which their Lovingness does not have. Thus, their Lovingness too is Infinite, Eternal, Living, Someone, a Person, God."

Although the Trinity is a mystery, we know it is not a contradiction. We can make some sense of it. The references we use for God--Father, Son, and Holy Spirit--are not images, but realities grounded in the fullness of existence. God is a family of three persons united by their infinite knowledge and love of each other. Knowing this is significant because the true purpose of creation and human existence is caught up in this one reality.

The Catechism says that the Trinity is ". . .the source of all the other mysteries of faith, the light that enlightens them. It is the most fundamental and essential teaching in the 'hierarchy of the truths of faith.' The whole history of salvation is identical with the history of the way and the means by which the one true God, Father, Son, and Holy Spirit, reveals himself to [us]" and brings us into His family (234).


Michael Terheyden was born into a Catholic family, but that is not why he is a Catholic. He is a Catholic because he believes that truth is real, that it is beautiful and good, and that the fullness of truth is in the Catholic Church. However, he knows that God's grace operating throughout his life is the main reason he is a Catholic. He is greatly blessed to share his faith and his life with his beautiful wife, Dorothy. They have four grown children and three grandchildren.



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