what is trinity

Kevin DeYoung offers some thoughts on the doctrine of the trinity. Here's his simple working definition:

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. When the ancient creeds employ extra-biblical terminology and demand careful theological nuance they do so not to clear up what the Bible leaves cloudy, but to defend, define, and delimit essential biblical propositions. 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 the tricky (but learnable) 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.

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 or manifestations (like the well-intentioned but misguided “water, vapor, ice” analogy).
• Orthodox Trinitarianism rejects Arianism which denies the full deity of Christ.
• 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.”