By the title, you may think I'm asking what people are, but that's not the purpose of this post. I mean to ask what a person is when we think about God, and how that impacts our understanding of ourselves as persons. Christians have historically affirmed that there is one God in three persons. I think the "one God" part is fairly easy to comprehend, but what are persons and how can God be three of them? The idea is complicated, and it took the church a few centuries to find the language to express what we know about God from the Scriptures. I know that many Christians today are troubled by the fact that the doctrine of the Trinity developed over time. If that bothers you, I'd encourage you to check out my other post on the topic. This post will focus on understanding the meaning of "person" when we talk about God. Before I go further, I should give credit to Cardinal Joseph Ratzinger. He wrote an article on the subject that was incredibly enlightening, though a bit difficult for me at first. If you want to read it for yourself, you can find it here. I'm still learning, but here is my best shot at describing "person” as it relates to God, and in the process what it means for us to be persons as well.
Understanding Persons in the Trinity
The saying, "one God in three persons," originates with the church father Tertullian in the 3rd century. Specifically, he described God as "One substance, three persons." The meaning of "substance" is subject to much debate regarding its finer details, but the general meaning isn't overly complicated. "Substance" refers to what God is. It means "stuff," in the words of a former pastor of mine. To be clear, we don't mean that God is made of atoms and particles like we are. He is not made of any material thing, but He still exists and therefore is some kind of a substance. God is one substance, so we can say that the Father is God, the Son is God, and the Spirit is God. They all are one substance. Some certain attributes and properties are common to all three persons, and so we say that these belong the one substance, such as God's timelessness, power, knowledge, and will (all persons share this in common).
However, we must also say that the Father is not the Son nor the Spirit, and so on (like in the diagram). So while each person is God, the persons themselves are unique. How can this be? There are many passages in Scripture that we don't have time to discuss, but we can consider one important passage. In Mark 1, Jesus is baptized (Matthew and Luke also include this story). Verses 10 and 11 say, "As soon as he came up out of the water, he saw the heavens being torn open and the Spirit descending on him like a dove. And a voice came from heaven: “You are my beloved Son; with you I am well-pleased." All at once, Father, Son, and Spirit show up. The voice from heaven spoke like a father to a son. It obviously wasn't Jesus' voice, nor the voice of the Spirit descending like a dove. Are we to say then that the three are different gods or substances? Absolutely not, because the Bible forbids this (Dt. 6:4). So we have to say that there is one God and that the Father, Son, and Spirit are all God and yet somehow not each other (See Jn. 1:1, 10:30). In light of this, to speak rightly about God, we must not blend the persons nor divide the essence, to quote the Athanasian Creed (read it here).
So we describe them instead as persons. Our word "person" comes from the Latin persona, which translates the Greek prospon. Prosopon originally referred to the masks actors wore in plays, and later came to describe their role as a whole. Christians like Tertullian took the word and instilled it with new meaning to describe God. In a play, you don't want to have a single narrator on stage telling you what happens in a succinct summary. You want to see the action unfold as the characters interact with one another. Narrators don't tell you what the characters did and said. You watch the characters speak and act. In the same way, when we read Scripture, we don't get recorded lectures about God. God is a character in the story who we learn about as He Himself speaks and acts. This is not to say that He is simply wearing different masks and playing different roles at different parts of the story (see my last blog). In the very beginning, God even speaks with Himself in the plural ("Let us make man in our image" Gen. 1:26), so the persons are not illusions, but actual realities within God. Therefore, Ratzinger says that "person" means "relation." The persons only exist because the other persons exist. The Father would not be the Father without the Son. The Son's existence implies the existence of a Father, and the Spirit (Greek: Pneuma, meaning breath, wind, or spirit) implies someone from whom the Spirit has come. Therefore, we give qualities to the individual persons that do not belong to all three, or the substance of God. For example, the Son is begotten, however, we cannot say that the Father or the Spirit is begotten. Both were involved in the begetting, but neither are begotten. Only the Son is. Or, we can say the Spirit is sent into the church. The Son and the Father have not been sent into our hearts. They are both involved in sending the Spirit, but only the Spirit is sent. This means that the identity of each person is actually dependent on the others. The Son is only the Son in relation to the Father, for example. Without His relationship to the Father, He would cease to be the Son.
The Person of Christ
If you've made it this far, pat yourself on the back. This isn't easy to understand, and it seems mostly useless at first, but the payoff is coming. Consider Christ: fully God and fully man. According to the council of Chalcedon, He has two natures in one person (you can read the whole confession here). This post is already long, so I won't spend time arguing for that idea. As a matter of explanation, what we mean is that Christ has the full nature of God and the full nature of humanity in one person. There are not two Christs. You cannot talk to Christ the God or Christ the man. You simply talk to Christ. He is one person or one relation. Because Christ is the second Adam (1 Cor. 15:45), we learn from Him what it is to be truly human, and that means we learn what it is for us to be persons.
Consider that Jesus' identity as Son comes only because of His relationship to the Father. He can't be the Son without the Father. Jesus' identity as Son was not found within Himself but in His relationship towards the Father. By becoming a man, He did not sacrifice any of His oneness with God, but neither was His humanity diminished by His union with God. He was most fully Himself precisely because of His union with the Father. This has powerful implications for what it means for us to be human persons.
Understanding ourselves as persons
We mistakenly tend to think that our identity is found on the inside; that if we look within ourselves, we will find who we truly are, and that we must then seek to change ourselves and the world around us to fit with who we are inside. This philosophy is so prevalent today that we take it for granted. This is the philosophy driving the transgender movement. According to the movement, what you are to other people doesn't matter. Your true self is inside your heart and mind, and if you search deep enough, you will find it. You may find that who you are on the inside doesn't match who you are on the outside, and so your body must be altered to match your mind. Going even further, the other persons around you and society itself must conform their thought and speech to affirm your internal identity. However, in doing this, identity becomes infinitely malleable, ever-changing with each person's whims. Personhood is effectively turned into an exercise of our imagination rather than a reality.
In Matthew 16:25, Jesus says, "For whoever wants to save his life will lose it, but whoever loses his life because of me will find it." Following the example of Christ, we don't find our identity as human persons by cutting ourselves off from others and looking inside. Rather, we are persons precisely because of our relationship to others. Our relations to others defines us as a person. Without another "you," there is no real "I." I am only a unique person because I stand in contrast to someone else. I did not make myself up on my own but was immediately born into a series of relationships that have defined who I am. To be most fully myself, I must put myself in relationship with that which is most different from me: God. God is so totally different from me. I am finite, limited, and temporary. But when I surrender my life to God and come into harmony with Him that I become most fully myself. Rather than looking inward, I look upward. In doing so, I don't lose myself in God, but I become more uniquely myself as I stand in contrast to Him, while yet being in harmony with Him. It is my relationship with God that makes me most fully the person that I am. By surrendering my life to Him, I have found it again, and more abundantly than ever.