The reason that it is important to affirm that the Father, Son, and Spirt are homoousios as well as being three distinct persons is simply because if we are to be monotheists, we must affirm the unity of the Godhead. To create a disunity in substance is to become polytheistic. There is no way around this. God cannot be one if the three persons of the Trinity are all of a different being and substance. This posits that they are distinct, not simply according to their personhood, but also according to their very nature. Three persons of three different natures ultimately results in three gods.

However, with this being said, the affirmation of monotheism cannot make it such that the Father, the Son, and the Spirit are identical as it relates to them as persons. First, if we conflate their persons, falling into modalism or other articulations similar to that, we cannot make sense of Scripture. Why does Jesus pray to the Father if he is the Father? (John 17:1). Why does the Father speak of Christ as his "beloved Son" if he is the Son? (Mt 3:17). Why does Jesus refer to the Holy Spirit as a "he" if he is the Spirit? (John 14:25). All of these moments in Scripture logically lead to the conclusion that the Father is not the Son or the Spirit; that the Son is not the Father or the Spirit; and that the Spirit is not the Father or Son.

So, in the end, we are left with both the confession of Scripture that God is one with the explicit multiplicity in that one God. The fathers of the Church saw this too and concluded that in order to make sense of this, one had to speak of God both in terms of "one" and "triune." Thus, God is one, with Father, Son, and Spirit of one substance and yet distinct according to their personhood. These are not different gods, but all the very nature of the one God of Abraham, Isaac, and Jacob.

The conversation surrounding perichoresis is helpful in that it further expresses—imperfectly of course—the way in which multiplicity can exist within perfect unity. In the words of Metropolitan Ware: "Father, Son, and Holy Spirit 'coinhere' in one another, each dwelling in the other two through an unceasing movement of mutual love - the 'round dance' of the Trinity" (8). This is helpful because it maintains that while the persons are distinct, they are not distinct in the way three human beings are distinct. Much of the trouble people have in understanding the Trinity is taking analogy too far. Three distinct persons in the Triune nature of God do not exist as separate individuals with different wills and actions as humans do. Instead, the unity of the persons in the Trinity is found in that they mutually indwell in one another, such that Christ can say, "Whoever has seen me has seen the Father" (Jn 14:9 ESV), and Scripture can elsewhere speak of the Holy Spirit as "the Spirit of Christ" (Rom. 8:9). This is not a confusion of the Persons of the Trinity, but rather an affirmation of their mutual indwelling of one another—in other words, their unity as sharing one homoousios. I find the emphasis on perichoresis to be one of the most helpful categories in demonstrating the oneness of the Godhead while still maintaining his Triune nature.

Works Cited:

The Holy Bible. English Standard Version. Crossway, 2016.

Ware, Timothy. "The Human Persons as an Icon of the Trinity." www.scribd.com/document/193755204/The-Human-Person-as-an-Icon-of-the-Trinity#scribd. Accessed 28 Mar. 2024.