What Is a Divine Person?
Augustine shows how God is Father, Son, and Spirit in that each relates to one another eternally as the one God of Israel.
Christian theology calls Father, Son, and Spirit divine persons. But what is a divine person?
The question is important, because I have seen prominent Christians question the traditional definition that divine persons are eternal relations in God. And I have seen many confuse modern definitions of person with the theological definition. The word person in classical theology has zero correspondence to contemporary definitions of a person as a psychological and conscious centre.
If not, then what is a divine person? And what could the phrase “divine persons are eternal relations in God” mean? I hope to answer both of those questions here and now.
Relations
Augustine reasons biblically and so often does not use technical language like persona and substantia while speaking of the Father and Son. For example, in his tractate on John 8:25–27 (Tractate 39), Augustine shows how the Father and Son are what they are because they are Father and Son without recourse to such language:
“For instance, a man and another man, if the one should be a father, the other a son. That he is a man is in respect to himself; that he is a father is in respect to the son. And that the son is a man is in respect to himself; but that he is a son is in respect to the father. For the name father has been said in respect to something, and son in respect to something; but these are two men. But in truth, God the Father is Father in respect to something [ad aliquid], that is, to the Son; and God the Son is Son in respect to something [ad aliquid], that is, to the Father. But as those men are two men, not so are these two Gods” (§4).
These relations of one to the other constitute the shared life of God. But they do so precisely because God is Life itself.
Life
Commenting on John 5:26 (Tractate 19), “For as the Father has life in himself, so he has granted the Son also to have life in himself,” Augustine shows how Father and Son are both the Life of God as Father and Son.
“The Father is life, not by a “being born”; the Son is life by a “being born.” The Father [is] from no father; the Son, from God the Father. The Father, in that he is, is from no one; but in that he is the Father, he is in regard to the Son. But the Son, both in that he is the Son, is in regard to the Father, and in that he is, is from the Father” (§2)
And little later:
“Therefore, the Father remains life, the Son also remains life; the Father, life in himself, not from the Son, the Son, life in himself, but from the Father” (§4).
So while Father and Son are what they are because the Father relates to the Son as Father, and the Son relates to the Father as Son, they both are through this mode of existence Life Itself. God is overflowing life because he is Father and Son—Life unbegotten, Life begotten, or Life from Life.
Simplicity
This relational mode of existence between Father and Son then points to the unity of their shared Life. Put another way, it requires a non-material existence that does not admit division or complexity of Being—or else Life would be Life 1 and Life 2. But there is one Life by which God is Life, and God does not lack Life only to beget Life later to gain life by participation. He is Life.
Hence, Christian theology requires a strong sense of divine simplicity to ensure that the mode of life that the Father and Son share in the eternal relation of Father to Son, and Son to Father, does not amount to two gods or polytheism.
Conclusion
God is Father and Son, and the Father is not God without the Son, and Son is not God without the Father. While I have for economy’s sake not mentioned the Spirit, I would also affirm that God the Father is not God without the Son or the Spirit, but is God in relation to the Son and Spirit.
To say God exists as eternal relations is to say that he is the Father, Son, and Spirit. God is the Father ad aliquid (the Son), the Son ad aliquid (the Father), and the Spirit ad aliquid (Father and Son). Together, God is Life itself—Life from Life from Life.
To say otherwise may suggest that we can think of God apart from being Father, Son, and Spirit. But that is not the God whom Christians worship. We worship that God who is eternally the Father of the Son, the Son who is eternally from the Father, and the Spirit who is eternally from the Father through the Son.
So important. How can we revive the teaching of eternal relations of origin in our normal discipleship practices?
When I first learned of eternal relations the trinity became so much more vibrant to me. Why is it still so rarely taught at a lay level? Great post.