In the previous two articles (part 1 and part 2), we have examined the first two principles of the Trinity: (1) there is one and only one God, and (2) that there are three co-equal Persons who are God: the Father, the Son, and the Holy Spirit. We saw that the Bible very clearly teaches these truths and does so in many different places and in many ways.
We now examine the third and final principle of the Trinity, which is this: the three Persons of God are each fully God and are eternally distinct from each other. In other words, the Father is not the Son or the Spirit, nor is the Son the Spirit, but each is fully God and this has always been that way and will always be that way.
Defining the Terms
But what exactly do we mean by ‘Persons’? There are multiple definitions of this word, and so we will have to settle on one in order to begin our investigation. Some lexical definitions of ‘person’ involve terms like “human” or “body.” And clearly these are not what we mean when we talk about the Persons of the Trinity. Only the second Person of the Trinity (Jesus) has a body and a human nature (in addition to His divine nature). And even He did not have this before the incarnation.
In the biblical sense, a person is a rational individual who can count as a legal witness. In biblical law, certain crimes, such as murder, rape, or kidnapping require the death penalty (Leviticus 24:41; Exodus 21:12, 14, 16; Deuteronomy 22:25). However, this penalty may only be invoked if there are at least two persons who witnessed the crime and if the details of their testimony agree (Deuteronomy 17:6, 19:15; Numbers 35:30; 2 Corinthians 13:1; Mark 14:56, 59). We will find that each Person of the Trinity qualifies as one witness under biblical law. So, although God is one in essence or nature, He is three Persons each of whom communicates and loves the other two, and each of whom counts as a legal witness.
Misconceptions of the Trinity
Sometimes in examining a difficult concept, it is helpful to first clarify what the concept is not. We can avoid mistaken impressions about the Trinity by examining several contrary positions, and seeing how such positions are specifically refuted in Scripture. So, let us briefly examine a few heretical views regarding the nature of God.
Modalism is one of the most common misunderstandings of the nature of God. Its advocates teach that the Father, Son, and Holy Spirit are not distinct Persons, but rather three modes by which God expresses Himself. Think of one person who wears one of three different nametags depending on the situation. A modalist believes that God is the Father sometimes, the Son at other times, and the Spirit at still other times. There are a few different versions of modalism. Sabellianism is a fairly common version which teaches that the Father is God as pertaining to Creation, the Son is God as pertaining to redemption, and the Holy Spirit is God as pertaining to sanctification. In all versions of modalism, there is merely one Person who is God, but this one Person is called by different titles at different times.
Many verses in the Bible are contrary to modalism. For one, there are many verses that mention two or three Persons of the Godhead at the same time. A great refutation of modalism is found at the baptism of Jesus (Matthew 3:16-17; Mark 1:10-11; Luke 3:21-22). All three Persons of the Trinity are active at this baptism at the same time. Jesus, the Son, is being baptized, while God the Father (2 Peter 1:17) speaks from heaven, while the Holy Spirit descends on Christ as a dove. When Jesus prays to the Father in John 17:1-26, He is not praying to Himself! Rather, one Person of the Trinity is communicating to another Person of the Trinity.
Arianism is a heresy that teaches that Jesus was begotten of the Father at a point in time; Jesus is thus considered a created being and not coeternal with the Father. The founder of the position, Arius, taught that Jesus was indeed God, but that Christ was distinct from the Father, subordinate to Him, and not of the same “substance.” Arius argued that there was a time when the Son did not exist. Arianism is refuted by many verses in Scripture which show that the Son is eternal (John 17:5; Micah 5:2; Isaiah 9:6), has always existed as God along with the Father (John 1:1, 17:24), is the Creator of all things (John 1:3, 10; Colossians 1:16; Hebrews 1:2), and is equal to God the Father (John 5:18; Philippians 2:6). One of my favorite Old Testament prophecies about Christ being born in Bethlehem shows that Christ has eternally existed. Micah 5:2 states, “But as for you, Bethlehem Ephrathah, Too little to be among the clans of Judah, From you One will go forth for Me to be ruler in Israel. His goings forth are from long ago, From the days of eternity.”
Partialism is the view that the Father, Son, and Holy Spirit are each (perhaps) fully divine, but only components of the one God. The idea is that each is only partly God until they come together to form the complete God. However, the Bible treats each of the Persons of the Trinity as fully God, and any number of verses demonstrate this. Thomas didn’t say to Jesus, “One third of my Lord and one third of my God” but rather, “My Lord and my God” (John 20:28). Likewise, Christ’s blood isn’t one-third God’s blood, but is God’s blood (Acts 20:28). When Ananias lied to the Holy Spirit, he didn’t lie to one third of God, but rather he lied to God (Acts 5:1-5). By the way, God is infinite in many respects. And mathematicians know that dividing infinity by three is still infinity, and that the latter infinity is the same size as the original.
There are other heretical views of course. And each of these is rebutted by the Scriptures. So, let us now move on to discuss what the Bible states about the nature of the three Persons who are the one God.
Eternally Distinct Persons
The third principle of the Trinity is proved if the Bible does indeed teach that the Father, the Son, and the Holy Spirit are eternally distinct Persons. Having defined our terms, we can now examine the Scriptures to see if this is so. We begin in passages such as John 5:31-37, and John 8:16-18. In the latter passage, Jesus states, “But even if I do judge, My judgment is true; for I am not alone in it, but I and the Father who sent Me. Even in your law it has been written that the testimony of two men is true. I am He who testifies about Myself, and the Father who sent Me testifies about Me.”
So, Jesus claims that He and the Father constitute two witnesses in terms of biblical law. He even refers to Deuteronomy 17:6, 19:5, passages that teach that at least two witnesses are required to settle a matter of fact. In this case, Jesus testifies about Himself, and God the Father also testifies about Jesus. This proves that the Son and the Father are two distinct Persons, each of whom counts as a witness under biblical law.
If God were only one Person, then Christ’s argument would be absurd. He would be attempting to count Himself as two different witnesses simply by changing His name. Imagine a lawyer trying to prove his case by calling the same witness to the stand several times, but putting a different name tag on him each time. Would the judge and jury be impressed that the testimonies of this one individual all agree? For the testimony of the Son and the Father to count as two consistent testimonies under biblical law, the Father and the Son must be distinct Persons. Each is God. But the Father is not the same Person as the Son.
The Holy Spirit is the third Person of the Trinity because He too counts as one witness (1 John 5:6). In John 15:26, Jesus says of the Holy Spirit, “When the Helper comes, whom I will send to you from the Father, that is the Spirit of truth who proceeds from the Father, He will testify about Me.” This shows that the Holy Spirit counts as one witness under biblical law. Therefore, the Spirit is not the same Person as Jesus, for the testimony of the Holy Spirit will confirm the truth of Christ’s testimony. Furthermore, the Holy Spirit is sent by Jesus from God the Father, and is therefore not the same Person as the Father or the Son.
In addition, there is love and communication between the three Persons of the Trinity. The Father speaks to the Son (Psalm 110:1-4, 45:6-7; 2:7-9; Matthew 3:17, 17:5; John 12:28, 49-50; Acts 13:33; Hebrews 1:5, 9-12, 5:5, 7:21). The Son speaks to the Father (Matthew 11:24-26, 26:39, 42, 27:46; Mark 14:36; Luke 10:21, 23:46; John 11:41-42, 17:1-26; 12:28; Psalm 40:6-8; Hebrews 10:5-7). The Spirit speaks to the Father on our behalf (Romans 8:26), and He speaks to the Son in prophecy (Matthew 22:43-44; Mark 12:36; Psalm 110:1). In some cases, one Person of the Trinity speaks to the others, but which Person is speaking is not specified (Genesis 1:26, 3:22, 11:7-8).
Love Within the Trinity
The love between the Persons of the Trinity shows that they are truly distinct Persons and not merely different modes or characters of one Person. For example, the Father loves the Son (John 3:35, 10:17, 14:15, 15:9-10, 17:23,24,26) and the Son loves the Father (John 14:31). The noun form of the Greek term translated “love” in these passages is ἀγάπη “agape” (ag-ah´-pay) which, in its purest form, is a benevolent, selfless love (1 Corinthians 13:4-5; Romans 13:10). This term is used in John 15:13 where Jesus says, “Greater love has no one than this, that one lay down his life for his friends.” Of course, the Lord Jesus demonstrated His great love for us, dying for us even while we were His enemies (Romans 5:8)!
A selfless love within the Godhead is only possible if there is more than one Person who is God. After all, loving yourself is hardly selfless! And so, we begin to see that the biblical Trinity resolves a problem that is present in all non-trinitarian religions such as (but not limited to) Islam. The problem for such religions involves the reconciliation of two foundational truths:
(1) God needs absolutely nothing beyond Himself (Acts 17:24-25, Psalm 50:10-12, Isaiah 46:9-10).
(2) God is love. (1 John 4:8)
Many religions and cults would assert both premises to be true. Yet they cannot be reconciled apart from the Trinity. Before Creation, how could God be love if He were only one Person and no others existed?  If there is no one to love, how can love be an essential attribute of God such that He can be said to be love? Such a God would need to create something beyond Himself in order to love. Yet, this violates the first premise; God needs nothing beyond Himself.
The Christian God (1) needs nothing beyond Himself and (2) is love. This is because there has always been love between the Persons of the Trinity who are each fully the one God. And although God chose to create other creatures and bestowed His love upon them, He had no need to do so. He doesn’t need the physical creation to love, for the Father loved the Son even before the universe existed (John 17:24).
The Three Persons Are Eternally Distinct
The relationship between the Father, Son, and Spirit is an eternal one. God has always been one God, and three Persons. The Father has always been the Father, the Son has always been the Son, and the Spirit has always been the Spirit. In John 17:24, Jesus refers to the fact that the Father loved Him before the foundation of the world, showing that their relationship precedes time itself. The Son was with God and was God from the very beginning (John 1:1). The Son is eternal (Hebrews 13:8; Isaiah 9:6). Likewise, the Holy Spirit is eternal (Hebrews 9:14). The Spirit of God was present even when the world was being formed (Genesis 1:2). Thus, the three Persons of the Trinity have always been the three Persons of the Trinity.
The Trinity is eternal and unchanging because God’s nature is eternal and unchanging (Deuteronomy 33:27; Romans 16:26; 1 Timothy 1:17). Malachi 3:6 states, “For I, the LORD, do not change; therefore you, O sons of Jacob, are not consumed.” Since God does not change, and since He is triune, it follows logically that God has always been triune and will always be triune.
Each of the three Persons of the Trinity has the same nature since each is God. They are of the “same substance.” Hence, Jesus can say in John 14:9, “He who has seen Me has seen the Father.” It is not that the Father and the Son are the same Person, but they are the same being and hence have the same nature. Jesus therefore rightly says in John 10:30, “I and the Father are one.” To know Jesus is to know the Father (John 8:19). To deny the Son is to deny the Father (1 John 2:23). To honor the Son is to honor the Father (John 5:23). To hate the Son is to hate the Father (John 15:23). Having the same nature, the three Persons of the Trinity are equal in terms of power, glory, and being.
The Trinity in Redemption
God would be a Trinity even if He had decided not to create anything because it is His nature. This is called the ontological Trinity, or immanent Trinity. Ontology refers to the nature of being. However, God did create a universe. He knew that mankind would rebel against Him, and He had a plan from the beginning to redeem man. In His act of creating the universe and in redeeming His people, each of the Persons of the Trinity willingly took on a particular responsibility. The three Persons of the Godhead cooperate in order to bring about creation and salvation. We refer to this as the economic Trinity.
All three Persons were involved in the creation of the universe (Isaiah 64:8; Colossians 1:15-16; Job 33:4). Each had a particular role. For example, the Holy Spirit moved upon the surface of the waters at Creation (Genesis 1:2). The Son sustains (holds together) the creation even now (Colossians 1:17).
Moreover, each Person has a particular role in the salvation of believers. Out of love, God the Father sent the Son into the world to save believers (John 3:16-17, 5:37). The Son willingly submitted to the Father, obeyed Him, and laid down His life as a ransom for many (John 14:31, 4:34, 6:38, 8:42, 12:49; Matthew 20:28). The Father draws believers to the Son to be saved (John 6:37, 44, 65, 10:29, 17:6). The Son gives eternal life to believers (John 6:33, 10:28). The Father and the Holy Spirit bear witness to the Son’s ministry (John 8:18, 15:26). No one can come to the Father except through the Son (John 14:6). No one can proclaim that Jesus is Lord except by the power of the Holy Spirit (1 Corinthians 12:3).
The Father sends the Holy Spirit into the world at the request of the Son (John 14:16-17, 26). The Spirit glorifies the Son (John 16:14) and convicts the world of sin (John 16:7-8). The Father, the Son, and the Spirit resurrect believers (John 5:21, 6:40, 63). Jesus was raised from the dead by all three Persons of the Trinity, including Himself (John 10:17-18, 2:19, 21; 1 Peter 3:18; Acts 13:33, 2:32, 3:15, 4:10, 5:30, 10:40, 13:30, 37). The Spirit sanctifies believers (2 Thessalonians 2:13).
In many passages, all three Persons of the Trinity are mentioned according to what they are doing or have done (1 Peter 1:2; 2 Corinthians 13:14; Ephesians 3:14-19, 2:18; 2 Thessalonians 2:13; John 14:26, 15:26; Acts 2:33, 4:24-26; Galatians 4:6). Consider 1 Peter 1:2, which states, “according to the foreknowledge of God the Father, by the sanctifying work of the Spirit, to obey Jesus Christ and be sprinkled with His blood: May grace and peace be yours in the fullest measure.” So in this single verse, we see the foreknowledge of the Father, the sanctifying work of the Spirit, and the blood of Jesus Christ by which we are saved.
Three in One
All three Persons of the Trinity cooperate to accomplish salvation. These three have the same nature since they are the one God. The above verses refute any notions that the Persons of the Godhead have different natures or attitudes. Sadly, some people miss this and seem to think that the Father is wrathful and would be unwilling to save us except the Son is loving. But this is anti-biblical; it was the Father who loved the world so much that He sent His son to die (John 3:16-17). Conversely, the Son can rightly be full of wrath toward those who are evil (Revelation 6:16; Psalm 2:12). All the Persons of the Trinity are God; and God is both loving and righteous and willing to save the repentant. He is rightly angry with sin, and yet merciful to those who repent. All of God’s attributes as God are shared by each member of the Trinity.
And, as we saw in the previous article, all the members of the Trinity are Yahweh – the one and only God. Hence, Jesus can say in Matthew 28:19 that in making disciples of all nations, they are to be baptized “in the name of the Father and the Son and the Holy Spirit.” Notice that He does not say “names” but rather “name.” All the Persons of the Trinity have the same name: Yahweh (“LORD”).
An interesting example occurs in Genesis 18-19. Here, the Lord (Yahweh) takes on human form, along with two angels, to converse with Abraham (Genesis 18:1-2). The angels leave and go to Sodom (Genesis 18:22, 19:1), while the Lord remains and talks with Abraham. The angels tell Lot and His family to flee because the Lord is about to destroy Sodom. According to Genesis 19:24, the Lord on Earth then calls down fire and brimstone from the Lord in heaven. Yes, Yahweh on Earth calls to Yahweh in heaven.
Understanding the Trinity
Having established from the Scriptures that there is one and only one God, three Persons (Father, Son, Holy Spirit) who are equally and fully God, and that these Persons are eternally distinct, the Trinity is proved to be a biblical doctrine. Anyone arguing against the Trinity will necessarily be refuted by the Scriptures we have cited in these articles. But one potential difficulty remains: our inability to fully picture the Trinity or appreciate all its nuances.
This of course is not a logical problem. The concept of one God who is three in Persons violates no law or principle of logic. It may be counterintuitive, or hard or impossible to visualize. But that is logically irrelevant. Many things are demonstrably true that are difficult or impossible for the human mind to comprehend. However, some people will not submit or believe in a God that they cannot fully understand. This is not a logical problem with God, but a psychological problem with man. God has given us a universe of examples of things that can be proved to be true, and yet go beyond our ability to fully fathom. Consider the distances to other galaxies, or the energy expended in a supernova. Thanks to scientific notation, we can write down numbers to quantify such things, but do we really understand them?
Most people don’t fully understand the design and programming of the smart phone they use, but they are content to use it. And yet, some refuse to believe those things that God has said about His nature that they cannot fully comprehend. Is that rational? Could a finite being possibly fully understand an infinite being? We could spend eternity studying the nature of God without ever exhausting the richness of His infinite character.
So for those people who say, “But I don’t fully understand the nature of the Trinity,” I have good news: you don’t have to. As a finite creature you can’t fully understand the infinite depths of the nature of God. The Bible says that His ways and thoughts are as far above ours as the heavens above the Earth (Isaiah 55:8-9). God doesn’t require us to fully grasp His nature, as if we could. Instead, He simply requires us to have faith in Him – to trust what He says about His nature. We are to repent and believe the Gospel (Mark 1:15; Acts 20:21).
We have seen that the Gospel involves the participation of all three Persons of the Trinity. This is why the Trinity is an essential Christian doctrine. To be saved, we must respond to the call of the Holy Spirit to place our faith in the Son who was sent by the Father. We must trust in the God of the Bible, and that God is a trinity. Those who reject what God has said about His own nature, and make up a god that is easier to understand, will not enter the kingdom of heaven (Matthew 7:22-23). Only faith in the living God is a saving faith. And this is faith that God Himself graciously grants us (Hebrews 12:2, Ephesians 2:8). And so, we close with the words of the famous hymn:
Holy, holy, holy! Lord God Almighty!
Early in the morning our song shall rise to Thee;
Holy, holy, holy, merciful and mighty!
God in three Persons, blessed Trinity!
 The Father also loves the Son using “love” in the sense of friendship or brotherly affection as expressed by the Greek word φιλέω “phileo” (John 5:20). Any differences between the two terms are subtle. A detailed study of John 21:15-17 reveals that φιλέω and ἀγάπη can be nearly synonymous in certain contexts.
 I use the phrase “before Creation” somewhat non-literally since time itself is something God created at the beginning. Hence, there is no literal time before Creation. However, God is beyond space and time. And we can consider His timeless nature without respect to the physical creation since He is not contingent upon it. That is, if God had not chosen to create time, He would have still existed as God. But how could a unitarian God exist as love without a universe containing at least one other Person to love?
 Isaiah 9:6 lists several titles for the coming Messiah, including אֲבִיעַ֖ד which many English Bibles translate as “Eternal Father” or “Father of Eternity.” This is not a reference to the trinitarian Father since it is the Son who came as the Messiah. Rather, in Hebrew, the phrase “Father of X” often refers to the creator or author of X. We see this phrase in Genesis 4:20-21 applied to Jabal who invented tents, and to Jubal who invented musical instruments. Christ is therefore the author of eternity, for it is He who gives eternal life to those who believe in Him (John 6:27, 10:28, 17:2).
 The unchanging nature of God does not imply that God cannot act in time. God can “step into time” and do what He pleases. Nor does the unchanging nature of God preclude His taking on an additional human nature in time, as the second Person of the Trinity did. But the Son, as God, has always been and will always be God. The same is true of the Father and the Holy Spirit.
 Quantum entanglement comes to mind. It can be shown to be true, but no one other than God really seems to fully understand it.