Does one have to believe in the Trinity to be considered a Christian?
My answer: Yes.
In a time where doctrine is an unpopular topic of discussion in churches, the unfortunate result is that we have shelved one of the most fundamental beliefs of Biblical Christianity. In doing so, we have left people ignorant and given them permission to deny or reject the doctrine of the Trinity all the while still be considered a Christian.
As theologian Dr. James White states, the Trinity is indeed “forgotten” by most.
Why the Trinity is so essential in Christianity and necessary for the Christian to believe is because this is how God has revealed Himself. Through the pages of the Bible, God has revealed his nature to be triune. For an individual (or group) to dismiss it as unimportant, or reject it entirely puts them outside the realm of historic Christian orthodoxy.
Admittedly, the Trinity can be hard to understand and even the most dedicated, Bible-loving believers at times get confused at its definition. Let me start off by saying, that the Christian believes in one eternal and true God. We are Biblical monotheists (belief in one God). Deuteronomy 6:4 says, “Hear, O Israel: The LORD our God, the LORD is one”. That truth has been and will always be precious to the church.
However, where Christianity diverges from other monotheistic religions (like Judaism and Islam) is that this One God possesses a triune nature, meaning that there is one essence that exists in three distinct persons. These persons are Father, Son, and Holy Spirit and they are coequal, coeternal and unchanging in their character.
It is an important distinction to be made, especially when misunderstandings abound. Christians don’t believe in three gods or that God manifests himself in three persons rather there is one being existing in three distinct persons.
And we get our Trinitarianism from the Bible.
Contrary to some who like to believe there was a secret shadowy council, akin to the Illuminati, that conjured up Trinitarianism to keep political power and subjugate poor helpless people, that is simply not the case. In fact, those individuals who say such things are ignorant of church history.
No, the Roman Emperor Constantine didn’t invent the Trinity, nor did a select group of bishops in 325 A.D. convene and make up a doctrine to preserve their positions. Rather what happened in what is called the Council of Nicaea is that it reaffirmed what the Bible teaches: God’s nature is triune and Jesus is Deity.
So why is all this important? Because any denial does damage to the doctrine of Christ itself, the gospel and makes the Bible a convoluted mess of contradictions.
Without the Trinity the Bible contradicts itself. In the Old Testament you have clear statements that there is only one God (Deut. 6:4, Isa. 43:10) while in the New Testament, you have three distinct persons called God—The Father, The Son (Jesus) and the Holy Spirit. Understanding that God is triune helps us reconcile the Old and New Testament and brings to light that God is a god of loving relationship in the interaction within the Godhead and with us.
Secondly, at the very center of the doctrine of the Trinity is the person of Jesus Christ. The New Testament is replete with texts concerning the deity of Jesus and one, in particular, I want to highlight is found in John 20:28 where Thomas looks to the resurrected Christ and says, “My Lord and my God!”.
What is so striking is that Thomas calls Jesus “God”, which for a monotheistic Jew would be unthinkable and blasphemous. But he does and Jesus doesn’t rebuke Thomas for blasphemy, instead receives his worship, affirming that Christ is indeed God in the flesh (Jn. 20:29).
The very gospel is Trinitarian. The Bible adamantly declares that “God saves” and each member of the Godhead plays a part in the salvation of people. God the Father willed for salvation to happen according to his own purpose and grace (2 Tim. 1:8-9). God the Son came in the person and work of Jesus, dying for our sins and brings new life (2 Tim. 1:10). And finally, the person of the Holy Spirit dwells within us and helps us live in light of the gospel (2 Tim. 1:14).
Although the Trinity is a great mystery and a difficult doctrine to comprehend, it must be believed, defended and rejoiced in. The Trinity is who God is and how he works.