Understanding the Trinity may be impossible, but proving the Trinity is not especially difficult. You don't need to master theology and philosophy. All you need is one irrefutable argument. Here it is.
Deity of Christ: Case Closed
Understanding the Trinity may be impossible, but proving that the Trinity is scriptural is not an especially difficult task. One needs only to define the Trinity accurately, then show that the Bible teaches the details of the definition. It makes no difference whether the word "Trinity" appears in the text or not. It only matters if the doctrine is taught there.
The definition of the Trinity is straightforward: there is only one God and He subsists as three distinct persons: the Father, the Son, and the Holy Spirit. One God in three persons. Simple.
How to Prove the Trinity
If you want to prove the Trinity, then, all you need to do is show that three specific truths are taught in Scripture. First, there's only one God. Second, the Father, Son and Holy Spirit are truly distinct persons. Third, each has the essential attribute of deity. That's it.
The first item--the oneness of God--is virtually uncontested by those challenging the Trinity on Scriptural grounds. Almost all who hold Scripture in high regard acknowledge the famous Shema of Deuteronomy 6:1, ""Hear, O Israel! The Lord is our God, the Lord is one! "
The second, that the Father, Son and Holy Spirit are truly distinct persons, is denied by modalists like Oneness Pentecostals. They hold there is one God who manifests Himself in different "modes" at different times, sometimes as the Father and sometimes as the Son. The popular illustration of the Trinity that a man can be a father to his son yet, in other modes, a husband to his wife and a brother to his siblings is a fine illustration of this second-century heresy, and not the orthodox doctrine of the Trinity. In this view the Father and the Son are both fully God, but there is no genuine distinction between the persons, only a linguistic distinction.
The third, that the distinct persons are each fully God, is denied by Arians like Jehovah's Witnesses. Jesus and the Father are distinct persons, they say, but do not share the essential attribute of deity. Only the Father is God. Jesus is a lesser, created "god."
The Irrefutable Argument
My purpose is to answer the Arian challenge by giving an airtight, scriptural proof for the deity of Jesus Christ. This technique is so simple you should be able to sketch it out on a napkin from memory the next time someone knocks on your door.
Remember, you don't have to master every counter-argument to every verse thrown at you. All you need is one unequivocal textual proof to make your case. Here it is. It comes from the Gospel of John.
Most discussions of this nature focus initially on John 1:1. It says, "In the beginning was the Word, and the Word was with God, and the Word was God." That's the way your Bible reads. But the Jehovah's Witness's New World Translation renders the verse this way: "In the beginning the Word was, and the Word was with God, and the Word was a god."
The heated discussion that follows is almost never productive. Don't waste your time wrestling with Greek grammar neither of you understand. Just drop down two verses. Verse three says, "All things came into being by Him [the Word], and apart from Him nothing came into being that has come into being." The NWT is virtually the same: All things came into existence through him, and apart from him not even one thing came into existence."
Have your visitor read the verse out loud. Then take out a napkin or a piece of scratch paper and draw a large box. Explaining that this box represents everything that exists. Run a line right through the middle of the box, dividing everything that exists into two categories. It will look something like this:
On the left side write "all things that never came into being," that is, all things that exist but have never been created. Ask your friend, "What goes in that box?" If he says "God" he got the right answer. God is the only thing that exists that has never been created. God alone is eternal and uncreated. Put the word "God" in the left-hand side of your box.
Label the right side "all things that came into being," that is, all created things. Write "all created things" there. Everything in this box was created through Jesus, according to verse three. Ask your friend if he understands that. Now write "created through Jesus" outside the box and run an arrow to the right side. Your box should now look something like this:
Take a moment to point out to your guest how this illustration is structured. The larger box includes everything there is, was or ever will be. Each particular existent falls into one of two categories: created or not created.
According to the law of excluded middle either a thing was created or it wasn't created--there is no third option--so the categories are all-encompassing. According to the law of non-contradiction a thing can't be both created and not created, so the categories are mutually exclusive. Any particular thing has to be one or the other. It's very simple.
Next you're going to determine what category Jesus belongs in. Take a coin out of your pocket. Tell your guest this coin represents Jesus Christ. Hand him the coin and ask him to place Jesus in the category where He belongs.
The first impulse of a Jehovah's Witness, of course, is to place Jesus in the category of "all things that came into being" because that's what their theology dictates. In keeping with the teaching of Arius in the early fourth century, there was a time "when the Word was not." Jesus was the first created being and everything else was created by Jehovah through Jesus.
But John 1:3 doesn't allow that option. Look at the wording carefully. John says, "All things came into being by Him, and apart from Him nothing came into being that has come into being," or in the NWT,"...and apart from him not even one thing came into existence" (emphasis mine).
John says the same thing two different ways for emphasis and clarity: everything that ever came into being owes its existence to Jesus, who caused it all to happen. If Jesus caused all created things to come into existence, then He must have existed before all created things came into existence. Therefore, the Word could not have been created.
In other words, if Jesus created everything that has come into being, and Jesus also came into being (as they contend), then Jesus created Himself. He would have to exist as Creator before He existed as a created thing, which is absurd. Therefore, Jesus can't be placed in the square labeled, "all things that came into being."
Just a side note. Much is made of the Greek word dia, translated "by" in the first phrase, but can also be translated "through." But it makes no difference whether all things were created "by" Jesus or "through" Jesus with Jehovah as the agency (as the Witnesses suggest). The point is that in either case Jesus is existing before the creation of all things that ever came into being.
So, the coin can't be placed on the right. At this point your visitor may want to place Jesus somewhere on the paper outside the larger box. But, as we've seen, you can't do that. These categories are all-encompassing and mutually exclusive; there's no "place" outside to put Him. Everything goes on one side of the larger box or the other.
If Jesus can't be placed on the right side with created things, then He must go on the left with uncreated things, identifying Jesus as the uncreated Creator. Jesus is God.
I have only come across two rejoinders to this proof for Jesus' deity. Each is so weak it merely serves to bolster our argument.
The first goes something like this. "Wait a minute, Greg. You didn't read the verse carefully. You missed something in the text. Notice the phrase 'apart from Him.' The apostle excludes Jesus from the count in this verse. If you said, 'Apart from Billy, the whole family is going to Disneyland' you wouldn't mean that Billy wasn't part of the family, just that he wasn't included in the count. Every member of the family is going to Disneyland with the exception of Billy. In the same way, every created thing was created by Jesus with the exception of Jesus Himself. Jehovah created Jesus first, then Jesus created everything else."
Note that this rebuttal turns on the ability to replace "apart from Him" with the phrase "excluding Jesus." Allegedly they're synonymous. OK, let's try the replacement and see what happens. The verse then looks like this: "With the exception of Jesus, nothing came into being that has come into being."
If your brow is furrowed trying to figure this out, I'm not surprised. The reconstructed phrase is nearly nonsense. Strictly speaking, it means that Jesus is the only created thing that exists. Read it again and see for yourself. Obviously, the phrase "apart from Jesus" can't mean "with the exception of Jesus." These phrases are not synonymous.
"Apart from Him" means something entirely different. It means "apart from His agency." It's the same as saying, "Apart from me you'll never get to San Diego. I've got the car." Apart from Jesus' agency nothing came into being that has come into being. Why? Because Jesus is the Creator. He is God. That makes perfect sense in the context.
The second attempt at refutation comes from a handful of more sophisticated Arians who know better than to lean on the bent reed of the first rejoinder. They go back to the opening phrase "In the beginning" and note that it is anarthrous, that is, it has no article in the original Greek. Since John merely writes "In beginning" he could be meaning "in a beginning."
Jehovah created Jesus, the story goes, at some indeterminate time in the past. Then after some unspecified second beginning ("a beginning"), He created everything else through Jesus. The details of verse three apply only to what happens after this second beginning. That's the argument.
This grasping-at-the-wind is an example of what I call "Bedtime Story." Here the detractor tells a story to put your argument to rest, but like all mere stories there is no foundation in fact. Nothing in the details of the text itself suggests this alternate translation. In fact, even the NWT renders it accurately.
Further, it strains at a gnat and swallows a camel. A focus on the gnat in verse one misses the camel two verses later. The phrases "all things" and "nothing" in verse three admit of no time restrictions. The only alternate "facts" available are found in the wishful thinking of those whose theology demands another reading. It's clear from the text that Jesus is God.
Parrying the Counter-Attack
Objections that Jesus is distinguished from the Father in other passages (as when He prays to the Father in John 17) merely bolster our defense of the Trinity. Agreed, Jesus is not the Father. Jesus can talk to the Father because each is a separate person, but as Creator, Jesus shares the same divine essence as the Father. Remember our definition: there is only one God and He subsists as three distinct persons: the Father, the Son, and the Holy Spirit. Obviously, then we'd expect to find evidence of personal interaction among each of them.
Remember, don't let your guest play "What About?" and drag you all over the New Testament. Keep bringing the issue back to John 1:3. All other verses must be understood in light of the unmistakable fact that Jesus is the uncreated Creator.
One parting thought. This exercise also resolves the translation controversy of verse one. Is the Word fully God or merely "a god"? John's teaching in verse three makes unmistakable the intent of his opening remark: "In the beginning was the Word and the Word was with God and the Word was God."
And that settles it.
This technique is so simple you should be able to sketch it out on a napkin from memory the next time someone knocks on your door. Don't waste your time wrestling with Greek grammar neither of you understand. If Jesus caused all created things to come into existence, then He must have existed before all created things came into existence.
Remember, don't let your guest play "What About?" and drag you all over the New Testament. Keep bringing the issue back to the unmistakable fact that Jesus is the uncreated Creator.