The doctrine of the Trinity is one of the great fundamental doctrines of Christianity. Belief or disbelief in the Trinity marks orthodoxy from unorthodoxy. Human reason alone cannot fathom the Trinity, nor can logic explain it fully. Probably a more descriptive term would be Tri-unity, which suggests the three-in-oneness of God better than the word Trinity. God is trinal, not triple; three in one, not three-parted. [There is no good natural analogy to God’s nature—not eggs, 3 states of matter, etc.]
A definition of the Trinity must include the distinctness and equality of the three Persons within the Trinity as well as the unity within the Trinity. The doctrine of the Trinity asserts that one God exists indivisibly and eternally as Father, Son, and Holy Spirit. God is three persons in one essence. The divine nature subsists in three distinctions—Father, Son, and Holy Spirit. All three Persons possess the divine attributes, yet the essence of God is undivided. The Persons do not exist or act independently of one another.
One of the great criticisms of the doctrine of the Trinity is that the word is not found in the Bible. Further, there is no uncontested, clear statement of the Trinity in one particular passage in the Bible. Nevertheless, the biblical evidence strongly supports the doctrine.
Hints of the Trinity in the Old Testament.
While there is no clear statement of the Trinity in the OT, there is some evidence of it. The OT allows for and implies the existence of the Trinity.
Suggestions of plurality in the Godhead
- Genesis 1:1 – God (Elohim) is a plural noun.
- Genesis 1:26 – “Let us make man in our image.” C.f. also Gen 3:22.
- Psalm 110:1 – God’s name is applied to more than one person in the same text.
Suggestions of three persons
- Isaiah 48:16 – “The Lord God, and his Spirit hath sent me”
- Isaiah 61:1 – “The Spirit of the Lord is upon me.”
The Angel of the Lord
In Exodus 3:1–5, the Angel of the Lord is equated with God and worshipped as God. Most likely, this was a pre-incarnate appearance of Christ.
While the OT by itself does not furnish a sufficient basis for the doctrine of the Trinity, it does contain certain suggestions that are consistent with it. It is highly doubtful that OT saints held any true Trinitarian ideas. The OT stressed the unity of God (Deut 6:4–5), and OT saints were strict monotheists. The revelation concerning God the Son and God the Holy Spirit had to await the historical appearance of Christ and the works of the Holy Spirit.
New Testament proof of the Tri-Unity of God
Texts mentioning the three Persons
- Matthew 3:16–17 – At the baptism of Christ, the Son was in the water, the Father’s voice was heard from heaven, and the Spirit appeared in the form of a dove.
- Luke 1:32–35 – Persons named: the Lord God, Son of the Most High, the Holy Spirit
- Matthew 28:19 – Baptism formula: “In the name of the Father, the Son, and the Holy Spirit”
- 2 Corinthians 13:14 – Apostolic benediction: “The grace of our Lord Jesus Christ, the love of God, and the fellowship of the Holy Spirit.”
- Jude 20–21 – “But you, beloved, building yourselves up in your most holy faith and praying in the Holy Spirit, keep yourselves in the love of God, waiting for the mercy of our Lord Jesus Christ that leads to eternal life.”
Texts that draw a distinction between the three Persons of the Godhead teach that the Father, the Son, and the Holy Spirit are individual, distinct persons. The Father is not the same individual as is the Son, nor is he the same individual as the Spirit.
Texts asserting the equality of the three persons
- John 6:27, 20:17 – The Father is God.
- John 1:1, 5:23; Titus 2:13; Hebrews 1:8 – The Son is God.
- Acts 5:3–4 – The Holy Spirit is God.
- Matthew 28:19; 2 Corinthians 13:14 – The Persons are associated together in ways denoting equality.
Note: There is no fixed order in the naming of the Godhead. That is, the names Father, Spirit, and Son are given in different orders.
Other issues regarding the Trinity
The name “Son of God”
Some suggest the term “son of God” implies a lower stature than God himself. However, as we saw in Lesson 6, the term “son” as used in the Bible is a Hebraic expression suggesting that one partakes of the qualities of whatever one is said to be a son of. Jesus also called himself the “son of man,” that is, he was a man. Thus the phrase “son of God” implies that Jesus partakes of the qualities of God. The Jews understood this—they were ready to stone him for making himself equal with God (John 5:18).
The economic Trinity
Occasionally it appears as if one member of the Trinity is submissive or subservient to another member. For example, Paul states that “the head of every man is Christ; and the head of the woman is the man; and the head of Christ is God” (1 Cor 11:3). Jesus repeatedly said that he came to do the Father’s will, not his own (Mark 14:36; John 5:19). And since the Holy Spirit is sent by God, he must be of lesser stature than God or Jesus.
An understanding of the functional nature of the Trinity dismisses the idea of essential difference within the Trinity. While the Persons of the Godhead are essentially equal, there is a functional or administrative chain of command. This concerns what they do, not who they are. God the Son and God the Holy Spirit do the will of God the Father. The Father is the source, the Son is the means, and the Spirit is the active agent (Eph 2:18).
This does not imply that the Father is better or superior to the Son or the Spirit, but simply that there is functional differences based on differing roles. Inferiority or superiority is not the idea here. Just as a father is to be head of the household, yet is not essentially different or better than any other persons in it, so God the Father is head of the Trinity without any essential difference between any member of the Trinity.
1 John 5:7 – “For there are three that bear record in heaven, the Father, the Word, and the Holy Ghost: and these three are one.”
This verse directly supports the doctrine of the Trinity and is included in most versions of the Bible until the nineteenth century. But it appears in only three Greek manuscripts, all of which are late and of suspect nature. No church father quotes the verse, which is a significant fact, because had they known the text, they certainly would have used it in the Trinitarian controversies they were engaged in. It’s not found in the Latin until the fourth century. Erasmus did not include it in his first two versions of his Greek NT because he couldn’t find it in any existing Greek text. He included it reluctantly in his third and following editions, with a lengthy footnote asserting his disbelief in its authenticity. It was included in the KJV because the translators followed Greek manuscripts based on Erasmus’s third edition. Thus this text is of limited value in proving the Trinity. Fortunately, the existence of the Trinity can be easily proven from many other texts.
Misinterpretations of the Trinity
- Tri-theism: three separate gods rather than one God in three persons.
- Modalism: three roles or modes of existence. The one God manifests himself as Father, Son, and Holy Spirit.
- Arianism: the Son is a created being, “a god,” and thus inferior to the Father in nature or essence. Jehovah’s Witnesses are Arians.
The use of “only begotten” and “first born”
Critics of the doctrine of the Trinity often assert that Christ cannot be equal with the Father because he was begotten and is called the first born. However, the term “only begotten” does not necessarily suggest a beginning point in time, but rather the unique, one-of-a-kind quality of Jesus. The term “only begotten” could be translated “one-and-only.”
The term “first born” is based on the OT idea that the first born son inherits a double portion of the father’s estate and other privileges unique to the first born son. Figuratively, the word denotes special privilege, priority and supremacy (c.f., Ex 4:22; Col 1:18; Heb 1:6). Christ is the head of the church and supreme over all, and is thus the first born. The word emphasizes Christ’s position, not his birth or origin. Read Psalm 89:27.
Bible clearly teaches the doctrine of the Trinity and Christians have believed it for nearly 2000 years. We may not fully grasp its meaning or understand how three can be one, but we must believe that one God exists eternally and indivisibly as Father, Son and Holy Spirit.
- Must we thoroughly understand a doctrine in order to believe it? No.
- Why is denial of the Trinity such a serious error? Because it denigrates the nature of God. It says that Jesus and the Holy Spirit are not fully and equally God.
- What’s wrong with this statement?
The Bible calls God by the names Father, Son, and Holy Spirit. That does not mean that he is three persons. Actually, these are the titles of three roles that he has filled. This can be understood in the same way that a man can say, “I am a father, son, and husband.” A man can truly be all three, but he is still a single person. So it is with God.
The Bible teaches 3 persons, not 3 modes of operation. The above idea is called modalism—one God functions in different modes at different times. Refutation: All three members of the Godhead show up simultaneously (e.g., Matthew 3:16–17), which would be impossible if modalism was true.
 Paul P. Enns, The Moody Handbook of Theology (Chicago: Moody Press, 1989), 198.