(1) Deuteronomy 6:4 "Hear, O Israel! The LORD is our God, the LORD is one!"

Verse 4 is subject to various translations, though the statement is likely stressing the uniqueness of Yahweh and should be translated, "The LORD is our God, the LORD alone."

However, there is also a secondary emphasis-The Lord's indivisibility. This is apparent in most English translations. This confession clearly prepares the way for the later revelation of the Trinity, but how? "God" (Elohim) is a plural word, and the word one (the Hebrew, echad) refers to one in a collective sense. As such, it is used of the union of Adam and Eve (Gen. 2:24) to describe two persons in one flesh. Further, it is used in a collective sense, like one cluster of grapes rather than in an absolute sense as in Numbers 13:23 when the spies brought back a single cluster of grapes. Furthermore, the oneness of God is implied in those Old Testament passages that declare that there is no other God beside Yahweh, the God of Israel.

(2) Deuteronomy 4:35 "To you it was shown that you might know that the LORD, He is God; there is no other besides Him."

(3) Isaiah 46:9 "Remember the former things long past, For I am God, and there is no other; I am God, and there is no one like Me."

(4) Isaiah 43:10 "You are My witnesses," declares the LORD, "And My servant whom I have chosen, In order that you may know and believe Me, And understand that I am He. Before Me there was no God formed, And there will be none after Me."

(5) 1 Corinthians 8:4-6 "Therefore concerning the eating of things sacrificed to idols, we know that there is no such thing as an idol in the world, and that there is no God but one. For even if there are so-called gods whether in heaven or on earth, as indeed there are many gods and many lords, yet for us there is butone God, the Father, from whom are all things, and we existfor Him; and one Lord, Jesus Christ, by whom are all things, and we exist through Him."

(6) Ephesians 4:4-6 "There is one body and one Spirit, just as also you were called in one hope of your calling; one Lord, one faith, one baptism, one God and Father of all who is over all and through all and in all."

(7) James 2:19 "You believe that God is one. You do well; the demons also believe, and shudder."

While there is no explicit statement in the Old Testament affirming the Triunity, we can confidently say that the Old Testament not only allows for the Triunity, but also implies that God is a triune Being in a number of ways:

(1) The name Elohim, translated God, is the plural form of El. While this is what is called a plural of plenitude pointing to the power and majesty of God, it certainly allows for the New Testament revelation of the Triunity of God.

(2) There are many instances where God uses the plural pronoun to describe Himself (see Gen. 1:26; 3:22; 11:7; Isa. 6:8).

(3) In the creation account, both God the Father and God the Holy Spirit are seen in the work of creation. It is stated that God created heaven and earth (Gen. 1:1), but that it was the Holy Spirit who moved over the earth to infuse it with life in the sense of protecting and participating in the work of creation (Gen. 1:2).

(4) Writing about the Messiah, Isaiah reveals Him to be equal with God, calling Him the "Mighty God" and "Eternal Father" (Isa. 9:6).

(5) Several passages reveal a distinction of Persons within the Godhead.

• In Psalm 110:1, David demonstrates there is a distinction of Persons between "LORD," the one speaking, and the one addressed called by David, "my Lord." David was indicating the Messiah was no ordinary king, but his own Lord, Adoni (my Lord), one who was God Himself. So God the first Person addresses God the second Person. This is precisely Peter's point when He quotes this Psalm to show the resurrection of the Messiah was anticipated in the Old Testament.
• The Redeemer (who must be divine, Isa. 7:14; 9:6) is distinguished from the Lord (Isa. 59:20).
• The Lord is distinguished from the Lord in Hosea 1:6-7. The one speaking here is Yahweh, the Lord, yet, note the statement in verse 7, "I will have compassion … and deliver them by the Lord their God."
• The Spirit is distinguished from the Lord in a number of passages (Isa. 48:16; 59:21; 63:9-10).

(6) In the Messianic prophecy of Isaiah 7:14, God made it clear that the One who would be born of the virgin would also be Immanuel, God with us.

(7) Two other passages which imply the Trinity are Isaiah 48:16 and 61:1. In Isaiah 48:16 all three Persons are mentioned and yet seen as distinct from each other. See also Gen. 22:15-16.

The case for the Triunity of God is even stronger in the New Testament. Here it can be unequivocally demonstrated the Father is God, the Son is God, and the Holy Spirit is God. Furthermore, the New Testament teaches us that these three names are not synonymous, but speak of three distinct and equal Persons.

(1) The Father is called God (John 6:27; 20:17; 1 Cor. 8:6; Gal. 1:1; Eph. 4:6; Phil. 2:11; 1 Pet. 1:2).

(2) Jesus Christ, the Son is declared to be God.His deity is proven by the divine names given to Him, by His works that only God could do (upholding all things, Col. 1:17; creation, Col. 1:16, John 1:3; and future judgment, John 5:27), by His divine attributes (eternality, John 17:5; omnipresence, Matt. 28:20; omnipotence, Heb. 1:3; omniscience, Matt. 9:4), and by explicit statements declaring His deity (John 1:1; 20:28; Titus 2:13; Heb. 1:8).

(3) The Holy Spirit is recognized as God. By comparing Peter's comments in Acts 5:3 and 4, we see that in lying to the Holy Spirit (vs. 3), Ananias was lying to God (vs. 4). He has the attributes which only God can possess like omniscience (1 Cor. 2:10) and omnipresence (1 Cor. 6:19), and He regenerates people to new life (John 3:5-6, 8; Tit. 3:5), which must of necessity be a work of God for only God has the power of life. Finally, His deity is evident by the divine names used for the Spirit as "the Spirit of our God," (1 Cor. 6:11), which should be understood as "the Spirit, who is our God."

Ryrie writes: "Matthew 28:19 best states both the oneness and threeness by associating equally the three Persons and uniting them in one singular name. Other passages like Matthew 3:16-17 and 2 Corinthians 13:14 associate equally the three Persons but do not contain the strong emphasis on unity as does Matthew 28:19."18

The New Bible Dictionary, adds to this the following evidence:

The evidence of the NT writings, apart from the Gospels, is sufficient to show that Christ had instructed his disciples on this doctrine to a greater extent than is recorded by any of the four Evangelists. They whole-heartedly proclaim the doctrine of the Trinity as the threefold source of redemption. The outpouring of the Spirit at Pentecost brought the personality of the Spirit into greater prominence and at the same time shed light anew from the Spirit upon the Son. Peter, in explaining the phenomenon of Pentecost, represents it as the activity of the Trinity: 'This Jesus … being … exalted at the right hand of God, and having received from the Father the promise of the Holy Spirit, he has poured out this which you see and hear' (Acts 2:32-33). So the church of Pentecost was founded on the doctrine of the Trinity.

In 1 Cor. there is mention of the gifts of the Spirit, the varieties of service for the same Lord and the inspiration of the same God for the work (1 Cor. 12:4-6).

Peter traces salvation to the same triunal source: 'destined by God the Father and sanctified by the Spirit for obedience to Jesus Christ' (1 Pet. 1:2). The apostolic benediction: 'The grace of the Lord Jesus Christ and the love of God and the fellowship of the Holy Spirit be with you all' (2 Cor. 13:14), not only sums up the apostolic teaching, but interprets the deeper meaning of the Trinity in Christian experience, the saving grace of the Son giving access to the love of the Father and to the communion of the Spirit.

What is amazing, however, is that this confession of God as One in Three took place without struggle and without controversy by a people indoctrinated for centuries in the faith of the one God, and that in entering the Christian church they were not conscious of any break with their ancient faith.19

From the above evidence, it should be clear that the Scripture teaches God is one and three.

John 1:14 And the Word became flesh, and dwelt among us, and we beheld His glory, glory as of the only begotten from the Father, full of grace and truth.

John 1:18 No man has seen God at any time; the only begotten God, who is in the bosom of the Father, He has explained Him.

In John 1:18, the King James Version has huios, "Son," in place of theos, "God," and reads, "No man hath seen God at any time; the only begotten Son, which is in the bosom of the Father, he hath declared him."

Because to our mind the words "only begotten" suggest birth or beginning, some have tried to take the use of this designation of Jesus Christ to mean that Christ had a beginning, that He only became the Son of God. Such an understanding denies His eternality and also the concept of the trinity. So what does John mean by the term "only begotten?"

"Only begotten" is the Greek monogenes, a compound of monos, used as an adjective or adverb meaning "alone, only." Kittel writes: "In compounds with genes, adverbs describe the nature rather than the source of derivation(emphasis mine). Hence monogenes is used for the only child. More generally it means 'unique' or 'incomparable.'"20 In the New Testament the term occurs only in Luke, John, and Hebrews, but an instructive use is found for us in Hebrews 11:17 where it is used of Isaac as the monogenes of Abraham. Isaac was not the only Son of the Patriarch, but he was the unique son of the promise of God. The emphasis is not on derivation but on his uniqueness and special place in the heart of Abraham.

Vine has an excellent summary of the use of monogenes in John 1:14 and 18:

With reference to Christ, the phrase "the only begotten from the Father," John 1:14, R.V. (see also the marg.), indicates that as the Son of God He was the sole representative of the Being and character of the One who sent Him. In the original the definite article is omitted both before "only begotten" and before "Father," and its absence in each case serves to lay stress upon the characteristics referred to in the terms used. The Apostle's object is to demonstrate what sort of glory it was that he and his fellow Apostles had seen. That he is not merely making a comparison with earthly relationships is indicated by para, "from." The glory was that of a unique relationship and the word "begotten" does not imply a beginning of His Sonship. It suggests relationship indeed, but must be distinguished from generation as applied to man.

We can only rightly understand the term "the only begotten" when used of the Son, in the sense of unoriginated relationship. "The begetting is not an event of time, however remote, but a fact irrespective of time. The Christ did not become, but necessarily and eternally is the Son. He, a Person, possesses every attribute of pure Godhood. This necessitates eternity, absolute being; in this respect He is not 'after' the Father" (Moule).

In John 1:18 the clause "The Only Begotten Son, which is in the bosom of the Father," expresses both His eternal union with the Father in the Godhead and the ineffable intimacy and love between them, the Son sharing all the Father's counsels and enjoying all His affections. Another reading is monogenes Theos, 'God only-begotten.' In John 3:16 the statement, "God so loved the world that He gave His Only Begotten Son," must not be taken to mean that Christ became the Only Begotten Son by Incarnation. The value and the greatness of the gift lay in the Sonship of Him who was given. His Sonship was not the effect of His being given. In John 3:18 the phrase "the Name of the Only Begotten Son of God" lays stress upon the full revelation of God's character and will, His love and grace, as conveyed in the Name of One who, being in a unique relationship to Him, was provided by Him as the Object of faith. In 1 John 4:9 the statement "God hath sent His Only Begotten Son into the world" does not mean that God sent out into the world one who at His birth in Bethlehem had become His Son. Cp. the parallel statement, "God sent forth the Spirit of His Son," Gal. 4:6, R.V., which could not mean that God sent forth One who became His Spirit when He sent Him.