Trinitarians say that the one God is one and three. The Bible only says He is one.
Trinitarians say that Jesus has two natures, human and divine. The Bible only says he has a human nature.
Trinitarians want one to accept the trinity and hypostatic union as divine mysteries- they say that God has revealed these seemingly contradictory things. Both of these doctrines, they teach, are composed of two seemingly contradictory components, which together form a divine mystery, which, despite the apparent contradiction, must be taken on faith.
This might be fine, except for the fact that a major component of each of these supposed mysteries simply isn’t in the Bible- meaning that the doctrines designed to reconcile these contradictory components with each other are not divine mysteries, but man-made dilemmas. And these dilemmas are easily solved, not by appealing to mystery, but my sticking to only what’s revealed in the Bible- namely, that God is one, and Jesus is a man, the Son and Christ of God.
This line of reasoning is simple- but it holds true. For the Trinity to be an acceptable doctrine, it should be taught in the Bible. And for it to be taught in the Bible, at least two central components of the Trinity doctrine- that God is one, and that God is three, need to be present in the Bible. Yet, all through the Bible, God is only identified as being one. While He repeatedly declares His unity, He never says that He is three. One can search through the Bible from cover to cover, and will find countless declarations that God is one- but one will never ever find even one statement which declares that God is three, or that God is three-in-one, or that He is triune, tri-personal, or any other such thing. The point here is simply this: a major necessary component of the doctrine of the Trinity is never taught by the Bible. On the other hand, that God is one is repeatedly and clearly expressed in both the Old Testament and the New.
There are passages, of course, which mention three persons; there are several instances in the Bible where the Father, Son, and Holy Spirit are spoken of as three; however, this is not the same thing as saying that the Father, Son, and Holy Spirit are all the one God. Unitarians also believe in Father, Son, and Holy Spirit -that these three exist is not at all the question at hand. Rather the question is, where are these three said to be the one God? None of the passages that mention these three together call them one God, or say that they are the same being- not a single passage. And in fact, in the majority of instances in which these three are mentioned together, the Father is simply called “God”, and the Son and Holy Spirit are distinguished as two others besides “God”. This fits perfectly with an understanding that God is one person, and that the Son and Holy Spirit are two others besides God, but does not support the notion that Father, Son, and Spirit are all one God.
Instances where Christ is called “God” or “a god” also don’t help the trinitarian case here; throughout the Bible, other beings besides the one God of Israel, YHVH, are called “gods”, including angels, and rulers in Israel, on account of the God-given authority and dominion they exercise within creation. In the case of Jesus, God’s human Messiah and Son, the title “God” (or “god”- there is no capitalization in NT Greek) serves the same purpose -a subject we shall return to later- denoting the God-given authority and dominion Jesus possesses as God’s appointed Lord over the universe.
As for the Holy Spirit being called “God” or “a god”, this is something which never occurs in the entire Bible. Where with Christ, the term “God” is at least applied to him, we have not even one clear instance of this with the Holy Spirit. There is one passage in Acts 5 which trinitarians often use as a proof-text for the Holy Spirit being God- but by the same logic some trinitarians use to try to ‘prove’ the Holy Spirit is God from Acts 5, one can also “prove” that the Holy Spirit is an angel from Acts 10. In fact, only by employing faulty logic and sloppy exegesis can either conclusion be achieved. Acts 5 never clearly calls the Holy Spirit ‘God’- rather is declares that just as by lying to Peter, Ananias had lied to the Holy Spirit, so by lying to the Holy Spirit, Ananias had lied to God. This no more proves the identity of God and the Holy Spirit than it proves the identity of the Holy Spirit with Peter. (See also: Twelve Arguments Showing the Holy Spirit is Not the One God).
The fact that the Bible never clearly calls the Holy Spirit “God” is rather damning for the doctrine of the Trinity- if one of the persons who is supposed to be a member of this triune God is never even called “God” once in the Bible, then it can never be fairly claimed that the Bible teaches the one God is three persons. Were the Holy Spirit called “God” or “a god”, this would hardly prove the trinitarian case- but this cannot even be said to occur. This inconvenient truth about the Holy Spirit is often ignored by trinitarian apologists. But a chain is only as strong as its weakest link- if the Bible never even teaches the Holy Spirit is God, then it certainly cannot be said to teach that God is a Trinity.
This all begs the question, why should anyone believe that God is three, when God has never revealed this about Himself? If the one God never says it of Himself, Jesus never says it about God, or says about himself that he is a person of a triune God, and if the Holy Spirit, in all the scriptures he inspired, never saw fit to mention this supposedly important doctrine even once, then on what good grounds should we believe that God is three? This question is only aggravated by the fact that it seems obvious that for God to be both one and three is a contradiction, especially when it is asserted particularly that God is one and three in the same sense, as many trinitarians do.
Now, if God did indeed reveal that He is both one and three, then this contradiction need not bother us- God is far above us, and we might well accept it as a divine mystery; something God understands that we cannot, which should be accepted on the basis of God’s trustworthy testimony about Himself, despite the fact we cannot understand it. We ought to have no problem, inherently, with the idea of divine mystery, or with believing in something we cannot fully understand. The problem is, God never revealed this. If that’s true, then this will never be a matter of how much we trust God over our own understanding- rather its a matter of people trying to impose on us a very significant belief about God, which God has never revealed to us or given us any reason to believe about Himself.
Our loyalty must be to God, not mere tradition, or social acceptance. There’s a real social cost to not believing the doctrine of the Trinity- but that’s okay. We should desire first and foremost the truth about God, and trust God with the consequences of believing that truth. The fact that God only ever revealed that He is one, and never that He is three, should in itself cause us to reject the Trinity, and to insist that any who would have us believe it provide clear biblical proof that God has claimed to be not only one, but also three – and such proof they will not be able to find.
It ought to be our assumption, when we see that God has revealed Himself to be one, and is consistently spoken of as a single person (for instance, by the use of singular personal pronouns), that He is only one, and not three (for this three-ness appears to contradict His unity, which we already know is true); and anyone who would insist that we must also hold what appears to then be a contradictory notion about God, that He is also three in addition to being one, should not be heeded unless they can do so on the basis of irrefutable scriptural evidence. Otherwise, we risk carelessly compromising what God has clearly revealed about Himself for something He has not, a mere invention of men, or rather, doctrine of demons.
Hear O Israel! YHVH our God, YHVH is one.Deuteronomy 6:4
Test all things; hold fast that which is good.1 Thessalonians 5:21
When we consider the doctrine of the dual-natures of Christ, we are confronted with a similar situation as we are with the Trinity- two essential elements of the doctrine, which appear contradictory, are put together to form what is regarded as a divine mystery- that Jesus has both a human and a divine nature. However, the Bible only speaks of Jesus having a human nature, and never asserts that he possesses any other. One may scour the Bible from one end to the other on this subject, and find references to Christ being ontologically human abound- in the the Pentateuch, through the Prophets, and into the gospels, and in the writings of the apostles after, we repeatedly and clearly see Jesus predicted to be a man, said to have been a man, call himself a man, and be asserted again and again to have been a man by his apostles.
We need to consider what that means- to call someone a man includes, implicitly, a statement of that person’s nature. Jesus belongs to the human species, that’s the kind of being the Bible tells us he is, unambiguously. In not one of these cases where Jesus is called a man is his humanity ever qualified, either, as we might expect if he actually had another nature as well- never does a biblical author take the time to clarify or specify that their words should not be understood how they sound on a bare surface reading, as telling you that the kind of being Jesus is is a human being. The reader is left to understand that Jesus is a ontologically a man, and nothing else.
Surely this is the impression that those who were familiar with Old Testament prophecy about the Messiah had, when they heard their God would raise up a prophet like Moses from among their own brethren, and that the Messiah would be a descendant of David, and surely those who first heard the preaching of the apostles in the book of Acts would have understood nothing more than this either, as the apostles repeatedly declare Jesus to be a man, but never once in all their preaching mention him having a divine nature.
“Men of Israel, listen to these words: Jesus the Nazarene, a man attested to you by God with miracles and wonders and signs which God performed through Him in your midst, just as you yourselves know— this Man, delivered over by the predetermined plan and foreknowledge of God, you nailed to a cross by the hands of godless men and put Him to death.”Peter, Acts 2:22-23 NASB
All in all, then, the Bible gives us a clear picture of Jesus Christ as a man, and as having a human nature. The same cannot be said about having a second, divine nature. Not a single verse in the Bible asserts that Jesus has a “divine nature” or any nature other than a human nature. Instances where Jesus is referred to as “God” (or “god”-there is no capitalization in Greek), cannot reasonably be taken as referring to a nature Jesus possesses, because biblically speaking, Godhood is not a nature or a species to which an individual may belong, but rather, to be “God” or “a god” denotes dominion and authority. For this reason, human judges and rulers, and angels as well, are called “gods” in the Bible, without impiety or absurdity.
We see Godhood spoken of this way in respect to YHVH all the time- He is called the “God of Israel”, “God over all”, the “God of gods”, “the God of Abraham, Isaac, and Jacob”, etc. and is called “my God”, “your God”, “our God” etc. Why do the Bible, and the people who speak in it, employ all this possessive language? Notice that we wouldn’t speak in a similar way of some ontological attribute or species, but we would of other relational roles. This can be shown by an easy test: try inserting “eternal” into those phrases in place of the word “God”, and see if they make any sense. Then try inserting “King” or “Lord” and see if they sound sensible, and that should show you which of those sorts of things Godhood is parallel to in biblical thinking.
Biblically, then, a person being called “God” or “a god” does not denote an ontological status or a nature, nor does it identify that person with the one God, YHVH. If it did, God would have to be something much more than a mere Trinity in order to accompany the multitude of persons beside Father, Son, and Holy Spirit the Bible calls “gods”. But if we think about Godhood with a biblical mindset, we will understand that a person being called a “god” in the Bible simply denotes authority and dominion, and does not identify the person bearing the label with the “God of gods”, the one God, YHVH.
What we have then, is scripture clearly presenting the Messiah, Jesus, as a man, and never telling us that he is ontologically, or in respect to nature, something other than a man. Like other men in the Bible, he can be referred to as a god- that simply fits the pattern of how scripture speaks, and should be expected. If angels on account of their authority can be called “gods”, then how much more so can he who has been given all authority in heaven and earth by the only true God? If judges in Israel can be called “gods”, how much more so can he through whom God will judge the entire world? I would suggest it should not surprise us or bother in the slightest that the human Messiah is called ‘our god’ in light of all this. This isn’t a statement of nature, but of status and authority.
In light of all this, then we are given reason by the Bible to only think that Jesus has a human nature- no other nature is ever revealed to us. There is no reason, then, to try to embrace the apparent contradiction of single individual possessing two distinct natures- something which makes no sense, and which we have no example of with anything else in the universe. If the Bible revealed such a thing, we should accept it, trusting God’s wisdom above our own, and being content to not understand things that are above us. But as with the Trinity, God never revealed this. Our acceptance of such a doctrine then cannot be seen as a test of how much we trust God over our own reason, but rather, whether we will restrict ourselves to what God has actually revealed about His Son, or embrace something foreign to that revelation, which appears to contradict it.
We should be very cautious about accepting something which seems to contradict what God has revealed about Himself and His Son. When God reveals He is one, we should not be willing to accept the contradictory notion that He is three, unless He Himself reveals this to us. Likewise, when God reveals that His Son is a man, we should not be willing to accept the contradictory notion that he is also ontologically God, without some clear revelation from God on this point. Otherwise, if we accept these doctrines without warrant from God’s own revelation, we risk simply contradicting God on these important matters. And such clear revelation in favor of the Trinity and dual-natures of Christ, we do not have. With that being the case, no Christian can be said to have good reason to accept the doctrine that God is triune or that the man Jesus possesses a second, divine nature. Rather, we should embrace without reservation the clear biblical teachings that God is one, and that Jesus His Son and Messiah is a man.