God has revealed that He is three persons or centers of consciousness within one Godhead. Because the concept cannot be fully comprehended does not mean the doctrine cannot be accurately described or defined; however, precision here requires some technicality. One good definition of the Trinity is provided by noted church historian Philip Schaff:

It is important to note here that the Bible teaches both monotheism and trinitarianism. It teaches a monotheistic view—that there is only one true God—and a trinitarian view—that this one true God exists eternally as three persons. This triunity of God was defended from earliest times as Christian theologians and apologists were careful both to safeguard the unity of God against tritheism and also to maintain the respective deity of the three persons. As Gregory of Nyssa stated in his letter to Ablabius, "To say that there are three gods is wicked. Not to bear witness to the deity of the Son and the Spirit is ungodly and absurd. Therefore one God must be confessed by us according to the witness of Scripture, ‘Hear Israel, the Lord your God is one Lord’ (Deuteronomy 6:4), even if the word ‘deity’ extends through the holy trinity."²

In his Christian Theology, Millard J. Erickson offers six points that must be included in a proper understanding of the doctrine of the Trinity:

1. There is only one God.

2. Each person in the Godhead is equally deity.

3. The threeness and oneness of God constitute a paradox or an antinomy—merely an apparent contradiction, not a genuine one. This is because God’s threeness and oneness do not exist in the same respect—that is, they are not simultaneously affirming and denying the same thing at the same time and in the same manner. God’s oneness refers to the divine essence; His threeness to the plurality of persons.

4. The Trinity is eternal—there have always been three persons, each of whom is eternally divine. One or more of the persons did not come into being at a point in time or at some point in time become divine. There has never been any change in the essential divine nature of the triune God. He is and will be what He has always been forever.

5. The function of one member in the Trinity may for a time be subordinate to one or both of the other members, although this does not mean He is in anyway inferior in essence. Each person of the Trinity has had, for a period of time, a particular function unique to Himself. In other words, the particular function that is sometimes unique to a given person in the Trinity is only a temporary role exercised for a given purpose. It does not represent a change in His status or essence. When the second person of the Trinity incarnated and became Jesus Christ, He did not become less than the Father, although He did become subordinate to the Father functionally. In like manner, the Holy Spirit is now subordinated to the ministry of the Son (John 14-16), as well as to the will of the Father, but He is not less than they are. Certain examples may illustrate this. A wife may have a subordinate role to a husband, but she is also his equal. Equals in some business enterprise may elect one of their number to serve as head or a chairperson for a period, without any change in rank. During World War II, the highest ranking member of an aircraft, the pilot, would nevertheless carefully subordinate his decisions to the bombardier, a lower ranking officer.

6. Finally, the Trinity is incomprehensible. Even when we are in heaven and fully redeemed, we will still not totally comprehend God because it is impossible that a finite creature could ever fully comprehend an infinite being. Thus, "Those aspects of God which we never fully comprehend should be regarded as mysteries that go beyond our reason rather than as paradoxes which conflict with reason."³

This last point takes us to our next question.

Before we discuss what the Bible teaches about the Trinity, we must remember that this doctrine is something finite minds can never fully comprehend. The Trinity may be logically defined, but this is partly the problem because "the infinite truth of the Godhead lies far beyond the boundaries of logic, which deals only with finite truths and categories."⁴ In other words, as an infinite being, God can never be fully understood by any finite person. If we can’t understand something as basic as particle physics, who would argue we should be able to rationally comprehend all that an infinite God is? As Dorothy L. Sayers once stated in Current Religious Thought (1957), "Why do you complain that the proposition God is three in one is obscure and mystical and yet acquiesce meekly in the physicist’s fundamental formula, ‘two P minus PQ equals IH over two Pi where I equals the square root of minus one’ when you know quite well that the square root of minus one is paradoxical and Pi is incalculable?"

Consider that an ant could never comprehend all that a human being is, even if it tried. Yet, if a human being could somehow become an ant, it might be able to explain enough about what a human is so that the ant could gain something of an understanding as to what a human is.

When we consider that God is, quite literally, infinitely removed from men, the parallel suffers immeasurably. All we can truly understand about God is what He has revealed to us in the Bible. And while this does give us a great deal of accurate information, it obviously does not give us exhaustive information that plumbs the depths of His infinity. Indeed, one of the glories of eternal salvation (John 5:24; 6:47) will be that finite creatures will forever learn wondrous things about the inexhaustible glories and perfections of an infinite God. This heavenly knowledge will make the things learned on earth pale in contrast.

The problems inherent in fully comprehending the doctrine of the Trinity are also inherent in the person of Jesus Christ. The doctrine known as the hypostatic union assimilates all the biblical data in order to accurately describe the nature of the Incarnation. It declares that Jesus is undiminished deity and full humanity in one person. Jesus Christ is both God and man. Jesus is not part human and part divine—He is fully man and fully God.

Because of this He has two natures, one divine and one human. But He is not two persons—He is not schizophrenic. Further, He is one person with two different kinds of consciousness (divine and human). Also, He is one person with two wills (if He truly has two natures, then He must have two wills, one human and one divine); however, Jesus Christ never had a conflict of wills.

Christ’s two natures were not altered by their union within the one person of Christ. Both divine and human characteristics and deeds may be attributed to the person of Christ under any of His names, whether divine or human. Also, both the human and divine natures of Christ may be manifested during a single event. Finally, the union of Christ’s two natures was not altered by His death, burial, resurrection, or ascension but will remain throughout eternity.⁵

The above material illustrates the importance of precision for accurately formulating the biblical data—and also how easily misconceptions might arise concerning the nature of God. This is why God encourages and commands us to "Be diligent to present yourself approved to God as a workman who does not need to be ashamed, handling accurately the word of truth" (2 Timothy 2:15). Christians should therefore study the doctrine of the Trinity to know how to effectively deal with the biblical data and answer the arguments of those in opposition: "And the Lord’s servant must not quarrel; instead, he must be kind to everyone, able to teach, not resentful. Those who oppose him he must gently instruct, in the hope that God will grant them repentance leading them to a knowledge of the truth, and that they will come to their senses and escape from the trap of the devil, who has taken them captive to do his will" (2 Timothy 2:24-26).

Thomas à Kempis stated Christian priorities eloquently when he wrote:

Christians can please God by accepting what God has revealed and what the Church has formulated historically that is in accordance with biblical teaching.

Prior knowledge of the Trinity, especially in its theological formulation, is not necessary for a person to be saved. But once saved, it is vital for Christians to know the true nature of the God who has so graciously pardoned them. This explains why the Church has always recognized the importance of a proper understanding of God and maintained that those who reject the scriptural view of God, as long as they do so, cannot be saved.

The great Athanasian Creed of the Church declares,

Noted Church historian Philip Schaff comments as follows concerning the creed’s placing of a divine curse or anathema on those who reject the Trinity. He points out the Athanasian Creed

As Vladimir Lossky once put boldly in The Mystical Theology of the Eastern Church, "Between the Trinity and Hell there lies no other choice."⁸

In fact, it is noteworthy that an examination of religions that claim to be Christian yet deny the Trinity invariably reveals that they also deny other key Christian doctrines, such as salvation by grace through faith alone. In other words, without a proper respect for Scripture and its understanding of God, it is unlikely one will get much else correct biblically.

Throughout its history, the Christian church has maintained that in order to be faithful to the teaching of the New Testament, one must affirm at a minimum the following doctrines: 1) the doctrine of the trinity; 2) the doctrine of salvation by grace through faith; 3) the doctrine of the incarnation and sinlessness of Christ; and 4) the sacrificial death, atonement, and resurrection of Christ. It is almost exclusively true that those who deny point one, the Trinity, also deny point two and often points three or four as well.

As Dr. Harold O. J. Brown points out in his excellent historical survey Heresies, modalism, for example, makes the event of redemption almost a charade. Why? Because if the Son of God is not a distinct person, as modalism teaches, He can hardly represent us before God the Father. And if Jesus Christ is not a real, separate person from God the Father—One who can stand before Him, address Him and intercede for us—then what happens to the concept of substitutionary atonement? If Christ does not exist as a separate person, how did He pay for our sins on the cross to satisfy the justice of God the Father? Thus, Dr. Brown correctly states, "Where modalism prevails, the concept of... vicarious atonement, will necessarily be absent, and so modalism is sometimes adopted by those who object to the doctrine of vicarious atonement."⁹

In other words, if there is no Trinity then there is no incarnation and no objective redemption or salvation. There is no one who is acting as a mediator between God and man.

When the Trinity has been denied, the other chief articles logically related to it such as atonement, regeneration, and so on are almost always altered or abandoned. This is why theologian Loraine Boettner concludes,

10 Loriane Boettner, Studies in Theology (Nutley, NJ: Presbyterian and Reformed, 1980), p. 139.