I have a friend who is considering Christianity and he is stuck on the doctrine of the Trinity. Tom, this one’s for you.
So, what exactly do we mean when we talk about the Trinity? Writing in the early third century, in hisAgainst Praxeas, Tertullian is credited with first employing the words “Trinity”, “person” and “substance” to convey the idea of the Father, Son and Spirit being “one in essence — but not one in person”. Indeed, Tertullian writes,
“Thus the connection of the Father in the Son, and of the Son in the Paraclete, produces three coherent Persons, who are yet distinct One from Another. These Three are, one essence, not one Person, as it is said, “I and my Father are One,” in respect of unity of substance not singularity of number.”
This concept was established as church orthodoxy at the famous Council of Nicaea in A.D. 325. The Nicene Creed speaks of Christ as “God of God, Light of Light, very God of very God, begotten not made, being of one substance with the Father.”
It is this definition that I am going to assume in the discussion that follows. Succinctly, then, the doctrine of the Trinity may be defined thusly: Within the one being or essence that is God, there exists three co-equal and co-divine distinct persons — namely the Father, Son and Holy Spirit — who share that essence fully and completely. This concept is not to be confused with polytheism, which maintains that there are multiple gods. While orthodox Christianity emphatically holds there to be only one God, we nonetheless understand God to be complex in his unity. The concept is also not to be confused with the ancient heresy of modalism, which maintains that God exists in three different modes. The Son has never been the Father and the Holy Spirit has never been the Son or the Father. Modalism is refuted by the picture given to us in all four gospels (Matthew 3:16-17; Mark 1:9-11; Luke 3:21-22; John 1:32-34) in which the Holy Spirit descends on Jesus in the form of a dove and a voice is heard from Heaven “This is my beloved Son. With him I am well pleased.” Similarly, it should be noted that the Father, Son and Spirit do not each make up merely a third of the Godhead. Rather, each of the three persons is God in the full and complete sense of the word.
Having shown that Scripture emphatically rejects the notion that the Father, Son and Spirit are synonymous persons, only five propositions remain to be demonstrated in order to provide Biblical substantiation for the concept of the Trinity. Those propositions are:
- There is only one eternal God.
- The Father is the eternal God.
- The Son is the eternal God.
- The Holy Spirit is the eternal God.
- Although the Father, Son and Holy Spirit are non-synonymous persons, the concept of the Trinity does not violate the law of non-contradiction.
Let’s take a look at each of these in turn.
He then takes a close look at what the Bible says about God with respect to those assertions. There can be no doubt that the Bible teaches that God is one divine substance, and three persons.