A man named Arius came along and began to teach that Jesus was a good man, a superior man, but He wasn’t God. And the leaders of the church met together, a council, they called it. They studied the issue and they gave us the Athanasian Creed. Here’s what they arrived at, and I’ll never get over thanking God for these wonderful, learned, godly men. They said, “We worship one God in Trinity, and Trinity in Unity.”
I am a unitarian in that I believe in the unity of God. I am a trinitarian in that I believe in the trinity of God. And they’re not contrary one to the other.

We worship one God in Trinity, and Trinity in Unity;
Neither confounding the persons nor dividing the substance.
For there is one person of the Father, another of the Son, and another of the Holy Spirit.
But the Godhead of the Father, of the Son, and of the Holy Spirit is all one, the glory equal, the majesty coeternal.

I don’t know whether you’ll agree with me or not, but to me it is just like music to hear these old, godly, serious-minded church fathers set this out for all the ages. For the last 1,600 years, the Church has feasted on this:

Such as the Father is, such is the Son, and such is the Holy Spirit.
The Father uncreated, the Son uncreated, and the Holy Spirit uncreated.
The Father incomprehensible, the Son incomprehensible and the Holy Spirit incomprehensible.
The Father eternal, the Son eternal, and the Holy Spirit eternal.
Yet there are not three eternals, but one eternal.
As also there are not three uncreated nor three incomprehensible, but one uncreated and one incomprehensible.
So also the Father is almighty, the Son almighty, and the Holy Spirit almighty, yet there are not three almighties, but one almighty.
So the Father is God, the Son is God, and the Holy Spirit is God; and yet they are not three Gods, but one God.

Now that’s what we believe, my brethren: we believe in the three Persons, but one God.
The three Persons are three, but the one God is One. And this we believe. So when I talk about God, I mean the three Persons of the Trinity. You can’t separate them—“not dividing the substance,” said these old fathers. You can’t have God the Father except you have God the Son; you can’t have God the Spirit unless you have the Father and the Son, “for the Spirit proceedeth from the Father and the Son.” So when I’m talking about God, I’m talking about the Father, the Son and the Holy Spirit—not confusing their Persons, for there are three Persons. But everything that is true of the Father is true of the Son and the Holy Spirit. And everything that is true of the Son and the Holy Spirit is true of the Father. Let’s get that settled before we go any further.

A. W. Tozer and David E. Fessenden, The Attributes of God: Deeper into the Father’s Heart, vol. 2 (Camp Hill, PA: WingSpread, 2001–), 19–21.