The following is from Kevin DeYoung, a guy whose books and blog I have read and loved. I was planning on writing about the Trinity when I came across his thoughts first. He stated everything I wanted to say so well, that I decided to repost his thoughts here. I have cut a few sections out of his original post but it is all his work, not mine...
If any doctrine makes Christianity Christian, then surely it is the doctrine of the Trinity. The three great ecumenical creeds—the Apostles’ Creed, the Nicene Creed, and the Athanasian Creed—are all structured around our three in one God, underlying the essential importance of Trinitarian theology. Augustine once commented about the Trinity that “in no other subject is error more dangerous, or inquiry more laborious, or the discovery of truth more profitable.” More recently, Sinclair Ferguson has reflected on “the rather obvious thought that when his disciples were about to have the world collapse in on them, our Lord spent so much time in the Upper Room speaking to them about the mystery of the Trinity. If anything could underline the necessity of Trinitarianism for practical Christianity, that must surely be it!”
Yet, when it comes to the doctrine of the Trinity, most Christians are poor in their understanding, poorer in their articulation, and poorest of all in seeing any way in which the doctrine matters in real life. One theologian said, tongue in cheek, “The trinity is a matter of five notions or properties, four relations, three persons, two processions, one substance or nature, and no understanding.” All the talk of essence and persons and co-this and co-that seem like theological gobbledy-gook reserved for philosophers and scholars--maybe for thinky bookish types, but certainly not for moms and mechanics and middle-class college students.
So in a few hundred words let me try to explain what the doctrine of the Trinity means, where it is found in the Bible, and why it matters.
First, what does the doctrine mean? The doctrine of the Trinity can be summarized in seven statements. (1) There is only one God. (2) The Father is God. (3) The Son is God. (4) The Holy Spirit is God. (5) The Father is not the Son. (6) The Son is the not the Holy Spirit. (7) The Holy Spirit is not the Father. All of the creedal formulations and theological jargon and philosophical apologetics have to do with safeguarding each one of these statements and doing so without denying any of the other six. The Athanasian Creed puts it this way: “Now this is the catholic faith: That we worship one God in trinity and the trinity in unity, neither blending their persons, nor dividing their essence. For the person of the Father is a distinct person, the person of the Son is another, and that of the Holy Spirit, still another. But the divinity of the Father, Son, and Holy Spirit is one, their glory equal, their majesty coeternal.”
The two key words here are essence and persons. When you read “essence”, think “Godness.” All three Persons of the Trinity share the same “Godness.” One is not more God than another. None is more essentially divine than the rest. When you read “persons”, think “a particular individual distinct from the others.” Theologians use these terms because they are trying to find a way to express the relationship of three beings that are equally and uniquely God, but not three Gods. That’s why we get this confusing language of essence and persons. We want to be true to the biblical witness that there is an indivisibility and unity of God, even though Father, Son, and Holy Spirit can all be rightly called God. The Persons are not three gods; rather, they dwell in communion with each other as they subsist in the divine nature without being compounded or confused.
Confusing isn’t it? Sometimes it’s easier to understand what we believe by stating what we don’t believe.
Orthodox Trinitarianism rejects monarchianism which believes in only one person (mono) and maintains that the Son and the Spirit subsists in the divine essence as impersonal attributes not distinct and divine Persons.
Orthodox Trinitarianism rejects modalism which believes that Father, Son, and Holy Spirit are different names for the same God acting in different roles (like the well-intentioned but misguided “water, vapor, ice” analogy).
Orthodox Trinitarianism rejects Arianism which denies the full deity of Christ.
And finally, orthodox Trinitarianism rejects all forms of tri-theism, which teach that the three members of the Godhead are, to quote a leading Mormon apologist, “three distinct Beings, three separate Gods.”
Second, where is the doctrine of the Trinity found in the Bible? Although the word “Trinity” is famously absent from Scripture, the theology behind the word can be found in a surprising number of verses. For starters there are verses that speak of God’s oneness (Deut. 6:4; Isa. 44:6; 1 Tim. 1:17).
Then there are the myriad of passages which demonstrate that God is Father (e.g., John 6:27, Titus 1:4).
Next, we have the scores of texts which prove the deity of Jesus Christ, the Son—passages like John 1 (“the word was God”), John 8:58 (“before Abraham was born, I am”), Colossians 2:9 (“in Christ all the fullness of Deity lives in bodily form”), Hebrews 1:3 (“The Son is the radiance of God’s glory and the exact imprint of his being”), Titus 2:13 (“our great God and Savior Jesus Christ”)--not to mention the explicit worship Christ willingly received from his disciples (Luke 24:52; John 20:28) and the charges of blasphemy leveled against him for making himself equal with God (Mark 2:7).
Then we have similar texts which assume the deity of the Holy Spirit, calling Him an “eternal Spirit” (Hebrews 9:14) and using “God” interchangeably with the “Holy Spirit” (1 Corinthians 3:16 and 1 Corinthians 6:19; Acts 5:3-4) without a second thought.
Third, why does any of this matter? There are lots of reasons, but I want to focus on one primarily...
The Trinity matters for relationships. We worship a God who is in constant and eternal relationship with himself as Father, Son, and Holy Spirit. Community is a buzz word in American culture, but it is only in a Christian framework that communion and interpersonal community are seen as expressions of the eternal nature of God. Likewise, it is only with a Trinitarian God that love can be an eternal attribute of God. Without a plurality of persons in the Godhead, we would be forced to think that God created humans so that he might show love and know love, thereby making love a created thing (and God a needy deity). But with a biblical understanding of the Trinity we can say that God did not create in order to be loved, but rather, created out of the overflow of the perfect love that had always existed among Father, Son, and Holy Spirit who ever live in perfect and mutual relationship and delight.