Why the Doctrine of the Trinity is fundamental to Salvation

“There is none other God but one.” —I Corinthians 8:4

Holy Scripture teaches us that man is completely dependent upon God’s own self-revelation as the only source of man’s knowledge of God. God “dwelleth in the light which no man can approach unto, whom no man hath seen, nor can see” (I Timothy 6:16). Therefore, there can be no true knowledge of God by human self-investigation. God has revealed Himself both in creation and in His Word, the Holy Scriptures. The natural knowledge of God which we have from creation and resident in the conscience (Romans 1:20; Acts 14:15-17; 17:24-28; Romans 2:14-15) does not tell us who the true God is, nor does it provide us with the knowledge needed for salvation. The true, saving Christian knowledge of God only comes by the Word of God, Holy Scripture (II Timothy 3:15).

What does God’s Word tell us about God? Dr. Martin Luther sums up the Christian knowledge of God correctly when he says “The Holy Scriptures teach that God is absolutely one and that He is also three Persons, absolutely distinct” (St. L. X:177). The one, true God is the Holy Trinity! God is one in essence; but in this one essence there are three distinct Persons, the Father, the Son and the Holy Ghost. The Christian Church uses the term “Trinity” or “Three in One” to designate the doctrine that Holy Scripture teaches.

God’s Word declares God to be one in essence. On the fact: “Hear, O Israel: The Lord our God is one Lord” (Deuteronomy 6:4) and “there is none other God but one” (I Corinthians 8:4c). The so-called “gods” of the heathen are declared to be non-gods, nonexistent, vanities, nothings, spun out of man’s vain and idolatrous imagination. The Prophet Jeremiah declares: “Hath a nation changed their gods, which are yet no gods? But My people have changed their glory for that which doth not profit” (2:11). The prophet contrasts the true God as “the fountain of living waters” and the non-gods “broken cisterns, that can hold no water” (2:13) empty, and therefore utterly useless.

Worship of any such so-called “god” is the sin of idolatry, expressly forbidden by the only true God: “Turn ye not unto idols, nor make to yourselves molten gods. I am the Lord your God” (Leviticus 19:4). The Apostle Paul designates the so-called “gods” of this world as gods in name only, having no reality whatsoever, as complete nothings:

As concerning therefore the eating of those things that are offered in sacrifice unto idols, we know that an idol is nothing in the world, and that there is none other God but one. For though there be that are called gods, whether in heaven or in earth, (as there be gods many, and lords many,) but to us there is but one God, the Father, of whom are all things, and we in Him; and one Lord Jesus Christ, by whom are all things, and we by Him
(I Corinthians 8:4-6).

Holy Scripture also contains descriptions of idols, the false gods invented by the heathen, which show that they are all rightly termed vanities (Acts 14:15; see also Isaiah 44:6-20; Jeremiah 2:26-28; Psalm 115:1-9, 135:15-17).

As the one true God, the Holy Trinity demands and commands exclusive worship; the Holy Trinity is to be adored and served by all men as the only true God:

God spake all these words, saying, “I am the Lord thy God, which have brought thee out of the land of Egypt, out of the house of bondage. Thou shalt have no other gods before Me. Thou shalt not make unto thee any graven image, or any likeness of anything that is in heaven above, or that is in the earth beneath, or that is in the water under the earth. Thou shalt not bow down thyself to them, nor serve them; for I the Lord thy God am a jealous God, visiting the iniquity of the fathers upon the children unto the third and fourth generation of them that hate Me, and showing mercy unto thousands of them that love Me and keep My commandments”
(Exodus 20:1-6).

And the Lord Jesus Himself declared: “The first of all the commandments is, ‘Hear, O Israel; the Lord our God is one Lord. And thou shalt love the Lord thy God with all thy heart, and with all thy soul, and with all thy mind, and with all thy strength.’ This is the first commandment” (Mark 12:29-30). Therefore, all who worship other “gods” must turn from such idolatry in true repentance, by the grace and power of God. The Apostle Paul and Barnabas cried out to the idolaters in their midst: “Turn from these vanities unto the living God” (Acts 14:15). The Bible also exposes the true nature of idolatry by revealing the demonic nature of such deception: “What say I then? That the idol is anything, or that which is offered in sacrifice to idols is anything? But I say, that the things which the Gentiles sacrifice, they sacrifice to devils and not to God; and I would not that ye should have fellowship with devils” (I Corinthians 10:19-20).

Only Holy Scripture reveals to man the true God, the Holy Trinity, one God in three distinct Persons, the Father, the Son and the Holy Ghost (Matthew 28:19). The Bible tells man that only this one God must be worshiped, with all three Persons receiving equal worship. Many times Scripture warns against failing to give equal honor to all three. In particular, the Scripture speaks of giving equal honor to the Father and to the Son: “That all men should honor the Son, even as they honor the Father. He that honoreth not the Son honoreth not the Father, which hath sent Him” (John 5:23; cf. I John 2:23, 5:12). Each person in the Godhead is the entire God; each Person has the whole divine essence without division or multiplication. Again Dr. Luther: “Of these Persons each one is the whole God beside whom there is no God” (Cited in J. T. Mueller, Christian Dogmatics, p. 148). For example, of the Son we read: “In Him [Christ] dwelleth all the fulness of the Godhead bodily” (Colossians 2:9). “In whom [Christ] are hid all the treasures of wisdom and knowledge” (Colossians 2:3). Each Person has one and the same essence with all its divine attributes, as Christ declares: “I and My Father are one” (John 10:30; cf. John 5:17, 19; 10:37).

Article I of the Apology of the Augsburg Confession affirms the clear doctrine of the Holy Trinity:

We declare that we believe and teach that there is one divine essence, undivided, etc., and yet, that there are three distinct persons, of the same divine essence and coeternal, Father, Son, and Holy Ghost. This article we have always taught and defended, and we believe that it has, in Holy Scripture, sure and firm testimonies that cannot be overthrown. And we constantly affirm that those thinking otherwise are outside the Church of Christ and are idolaters and insult God
(Triglot, p. 103).

This truth the Athanasian Creed professes as follows:

We worship one God in Trinity, and Trinity in Unity; neither confounding the Persons nor dividing the Substance. For there is one Person of the Father; another of the Son, and another of the Holy Ghost. But the Godhead of the Father, of the Son, and of the Holy Ghost is all one: the glory equal, the majesty coeternal. Such as the Father is, such is the Son, and such is the Holy Ghost … So likewise the Father is almighty, the Son almighty, and the Holy Ghost almighty. And yet they are not three Almighties, but one Almighty. So the Father is God, the Son is God, and the Holy Ghost is God. And yet they are not three Gods, but one God …And in this Trinity none is before or after other; none is greater or less than another; but the whole three Persons are coeternal together and coequal, so that in all things, as is aforesaid, the Unity in Trinity and the Trinity in Unity is to be worshiped.
(Triglot, p. 33).

This truth is beyond human reason and incomprehensible to the human mind. Any attempt to do so is doomed to failure. All who believe this transcendent and sublime truth do so solely by the working of the Holy Ghost, who grants them such faith, as St. Paul testifies:

But God hath revealed them unto us by His Spirit; for the Spirit searcheth all things, yea, the deep things of God. For what man knoweth the things of a man, save the spirit of man which is in him? Even so the things of God knoweth no man, but the Spirit of God. Now we have received, not the spirit of the world, but the spirit which is of God, that we might know the things that are freely given to us of God, which things also we speak, not in the words which man’s wisdom teacheth but which the Holy Ghost teacheth, comparing spiritual things with spiritual. But the natural man receiveth not the things of the Spirit of God, for they are foolishness unto him, neither can he know them, because they are spiritually discerned”
(I Corinthians 2:10-14).

Human reason cannot accept what appear to it as contradictory truths, namely, that in the one and indivisible God each Person is the entire God, and yet there are three truly distinct Persons. So, for example, when the Son, the Second Person, became incarnate, He alone became man and not the Father, neither the Holy Ghost (cf. John 1:1-3, 14). When man refuses to accept by faith what Scripture declares to be true regarding the Holy Trinity, his human reason falls into error by either denying the Unity of God’s Essence or the Trinity of Persons.

What special terms has God provided us in His Word for our faith to enable us to maintain the real distinction of the three Persons without dividing the one Essence? We are given special terms which refer to the personal acts or inward, eternal operations of the Holy Trinity. To distinguish the Father and the Son, we have the word “begotten.” The Father has “begotten” the Son from eternity; and the Son is, therefore, eternally “only-begotten” (John 1:14). To distinguish the Holy Ghost from the Father and the Son, we have the word “proceeding.” The Father and the Son have spirated the Holy Ghost from eternity; the Holy Ghost “proceeds” from both Persons (John 14:26, 15:26). These eternal acts, not common to all three Persons, distinguish the individual Persons in the Godhead and provide terms to enable us to avoid confusing the Persons while maintaining the undivided Essence, the “Tri-Unity” or “Trinity.”

This transcendent, sublime doctrine is not found in any other “religion;” for it is beyond reason and is truly supernaturally revealed, found only in God’s self-revelation, Holy Scripture. As such, the doctrine itself shows that the true worship of God is the result of God’s work within man’s heart, filling him with true awe in humble fear, love and trust. Christ told the Samaritan woman: “God is a Spirit, and they that worship Him must worship Him in spirit and in truth” (John 4:24). It is also important to remember that fallen man is under the primal delusion of Satan, who told Eve “ye shall be as gods” ]literally, “like God”[ (Genesis 3:5), so that natural man is opposed to the true worship of God (“enmity against God” Romans 8:7) and even rejects the natural knowledge of God in his vain imagination and foolish heart, creating “idols” as a matter of course (see Romans 1:18-25) and thus changes “the truth of God into a lie” (Romans 1:25a) just as Satan did!

In the Athanasian Creed (Triglot, pp. 31-35; The Lutheran Hymnal, p. 53), we are warned that the Christian knowledge of God is necessary for salvation, together with the doctrine of the Gospel, of course:

Whosoever will be saved, before all things it is necessary that he hold the catholic faith, which faith except every one do keep whole and undefiled, without doubt he shall perish everlastingly. And the catholic faith is this, that we worship one God in Trinity, and Trinity in Unity, neither confounding the Persons, nor dividing the Substance. For there is one Person of the Father, another of the Son, and another of the Holy Ghost. But the Godhead of the Father, of the Son, and of the Holy Ghost is all one: the glory equal, the majesty coeternal. Such as the Father is, such is the Son, and such is the Holy Ghost. The Father uncreate, the Son uncreate, and the Holy Ghost uncreate. The Father incomprehensible, the Son incomprehensible, and the Holy Ghost incomprehensible. The Father eternal, the Son eternal, and the Holy Ghost eternal; and yet they are not three Eternals, but one Eternal, as there are not three Uncreated nor three Incomprehensibles but one Uncreated and one Incomprehensible. So likewise the Father is almighty, the Son almighty, and the Holy Ghost almighty; and yet they are not three Almighties, but one Almighty. So the Father is God, the Son is God, and the Holy Ghost is God; and yet they are not three Gods, but one God. So likewise the Father is Lord, the Son Lord, and the Holy Ghost Lord, and yet not three Lords, but one Lord. For like as we are compelled by the Christian verity to acknowledge every Person by Himself to be God and Lord, so are we forbidden by the catholic religion to say, There be three Gods, or three Lords. The Father is made of none, neither created nor begotten. The Son is of the Father alone, not made, nor created, but begotten. The Holy Ghost is of the Father and of the Son, neither made, nor created, nor begotten, but proceeding. So there is one Father, not three Fathers; one Son, not three Sons; one Holy Ghost, not three Holy Ghosts. And in this Trinity none is before or after other; none is greater or less than another; but the whole three Persons are coeternal together and coequal, so that in all things, as is aforesaid, the Unity in Trinity and the Trinity in Unity is to be worshiped. He, therefore, that will be saved must thus think of the Trinity.

Furthermore, it is necessary to everlasting salvation that he also believe faithfully the incarnation of our Lord Jesus Christ. For the right faith is that we believe and confess that our Lord Jesus Christ, the Son of God, is God and Man: God of the Substance of the Father, begotten before the worlds, and Man of the substance of His mother, born in the world; perfect God and perfect Man, of a reasonable soul and human flesh subsisting; equal to the Father as touching His Godhead and inferior to the Father as touching His manhood; who, although He be God and Man, yet He is not two, but one Christ: One, not by conversion of the Godhead into flesh but by taking the manhood into God; one altogether, not by confusion of Substance but by unity of Person. For as the reasonable soul and flesh is one man, so God and Man is one Christ, who suffered for our salvation, descended into hell, rose again the third day from the dead; He ascended into heaven; He sitteth on the right hand of the Father, God Almighty; from whence He shall come to judge the quick and the dead; at whose coming all men shall rise again with their bodies and shall give an account of their own works. And they that have done good shall go into life everlasting; and they that have done evil into everlasting fire.

This is the catholic faith, which except a man believe faithfully and firmly, he cannot be saved.

What proof passages bring out the fundamental nature of the doctrine of the Holy Trinity? There are many. Each of them makes the point abundantly clear. Consider what the Lord says in John 17: “And this is life eternal, that they might know Thee, the only true God, and [i.e. (Gk.) including] Jesus Christ, whom Thou hast sent” (v. 3). The Athanasian Creed observes this passage by connecting the knowledge of the True God, the Holy Trinity, with the knowledge of the saving work of the True God in sending the Son to be the world’s Savior. Dr. Luther likewise points to the connection between the doctrines of the Trinity and of the saving work of Jesus Christ:

Such revelation (of God’s most inner being, as three Persons in one divine essence) is in accord with God’s highest work and indicates His divine counsel and will, for God has decreed from eternity and accordingly revealed in the many Messianic promises that His Son should become man and die to reconcile lost mankind to God. Nothing could redeem us from the dreadful fall into sin and from eternal death except an eternal Person who has the power to destroy sin and death and to give eternal righteousness and life instead. For this no angel nor any other creature was sufficient. Only God Himself could accomplish this
(St. L. XII:632).

The incarnate Savior stresses this connection every time He declares His unity with His Father:

But Jesus answered them, ”My Father worketh hitherto, and I work.” Therefore the Jews sought the more to kill Him, because He not only had broken the sabbath, but said also that God was His Father, making Himself equal with God. Then answered Jesus and said unto them, “Verily, verily, I say unto you, The Son can do nothing of Himself, but what He seeth the Father do; for what things soever He doeth, these also doeth the Son likewise. For the Father loveth the Son, and showeth Him all things that Himself doeth; and He will show Him greater works than these, that ye may marvel. For as the Father raiseth up the dead and quickeneth them, even so the Son quickeneth whom He will. For the Father judgeth no man but hath committed all judgment unto the Son, that all men should honor the Son, even as they honour the Father. He that honoreth not the Son honoreth not the Father which hath sent Him. Verily, verily, I say unto you, He that heareth My word, and believeth on Him that sent Me, hath everlasting life and shall not come into condemnation but is passed from death unto life”
(John 5:17-24).

The Apostle John affirms:

And this is the record: That God hath given to us eternal life, and this life is in His Son. He that hath the Son hath life; and he that hath not the Son of God hath not life. …And we know that the Son of God is come, and hath given us an understanding, that we may know Him that is true, and we are in Him that is true, even in His Son Jesus Christ. This is the true God, and eternal life. Little children, keep yourselves from idols. Amen. (I John 5:11-12, 20-21). Whosoever denieth the Son, the same hath not the Father, (but) He that acknowledgeth the Son hath the Father also
(I John 2:23).

The Apostle Paul declares the end result of all who know not God and who believe not the Gospel of Christ:

And to you who are troubled rest with us, when the Lord Jesus shall be revealed from heaven with His mighty angels, in flaming fire taking vengeance on them that know not God and that obey not the Gospel of our Lord Jesus Christ, who shall be punished with everlasting destruction from the presence of the Lord and from the glory of His power when He shall come to be glorified in His saints and to be admired in all them that believe (because our testimony among you was believed) in that day
(II Thessalonians 1:7-10).

All who remain “idolaters” shall not “inherit the kingdom of God” (I Corinthians 6:9-10) because they are unbelievers. Scripture declares: “He that believeth on the Son hath everlasting life; and he that believeth not the Son shall not see life, but the wrath of God abideth on him” (John 3:36). Dr. Franz Pieper summarizes the point:

The natural knowledge of God cannot deliver us from an evil conscience. The Christian knowledge of God, however, calms the troubled conscience. In fact, it is our salvation. Scripture does not propose the doctrine of the Trinity as an academic question or metaphysical problem. With the proclamation that in the one eternal God there are three Persons of one and the same divine essence, Scripture combines the further gracious message that God so loved the world that He gave His only-begotten Son into death as the Savior from the guilt of sin and death; that in the fullness of time, the eternal Son became incarnate and by His vicarious satisfaction reconciled the world to God; and that the Holy Ghost engenders faith and thus applies to man the salvation gained by Christ. When the Christian confesses, “I believe in God the Father, Son, and Holy Ghost,” he is saying, “I believe in that God who is gracious to me, a sinner.”
(Francis Pieper, Christian Dogmatics, Vol. I, p. 378).

Those who do not believe the mystery of the Trinity simply do not believe in God as He has revealed Himself in Holy Scripture and do not accept the way of salvation found therein: “For God so loved the world, that He gave His only begotten Son, that whosoever believeth in Him should not perish but have everlasting life. …He that believeth on Him is not condemned; but he that believeth not is condemned already because he hath not believed in the name of the only begotten Son of God” (John 3:16, 18). Rightfully the Holy Ghost, through the Apostle, speaks against all forms of idolatry immediately after proclaiming the Gospel of Christ, “the power of God unto salvation” (Romans 1:16-32).

With the Apostle and the Roman Christians we say: “But God be thanked, that [we] were the servants of sin, but [we] have obeyed from the heart that form of doctrine which was delivered [us]” (Romans 6:17). For all who have been converted to saving Christian faith by the Gospel owe it to God’s grace and power alone, for Jesus’ Sake. God be praised, Father, Son and Holy Ghost, now and forever. Amen.

— E. J. W.