Monotheism and polytheism are mutually exclusive. The former believes in one God whilst the latter affirms more than one. Those who subscribe to the doctrine of the Trinity believe in One God who is distinct in three co-existent, co-eternal and co-equal Persons.
If we try to explain the Trinity by means of illustration or metaphor that will inevitably result in heresy. Instead we need to describe God in the way the Bible describes Him since that is the way that God has revealed Himself. One classic suggestion is that the Godhead could be compared with water, steam and ice but this is saying that there is one God in three forms. This is known as Unitarianism which is an old heresy. On the other hand a tiny minority would argue there are three Gods, though this is another ancient heresy known as Tritheism. The term ‘Trinity’ is not used in the Bible though the concept of the three Persons of the Godhead is found throughout the Bible commencing from the outset and continues until the end of Scripture.
The use of the plural title Elohim
In Genesis 1:1 the word ‘Elohim’ is used of God. Whilst this word is even used to describe human judges or leaders in some verses and in different contexts, the important point is that this word is used in the plural sense and in the beginning only God existed.
In the next verse, Genesis 1:2, His Spirit is hovering over the waters. Isaiah 63:10 mentions the Holy Spirit being grieved. This demonstrates that the Holy Spirit is a Person and is not a force.
Interestingly in Psalm 45:6-7 there is a Messianic reference where the word Elohim is used of Messiah and of God ‘Your throne, O God, is forever and ever; a sceptre of righteousness is the sceptre of your kingdom. You love righteousness and hate wickedness; Therefore God, Your God has anointed You with the oil of gladness upon Your companions.”
God speaks saying “Let Us”
There are several references when God speaks for Himself in a plural sense. When God created mankind, He said “Let Us make man in Our image (Genesis 1:26).” When God banished Adam and Eve from the garden of Eden, He said, “Behold, the man has become like one of Us (Genesis 3:22).”When God came down to Babel He said, “Come let Us go down and there confuse their language (Genesis 11:7).” When God called Isaiah, He said “Whom shall I send, and who will go for Us (Isaiah 6:8)?”
God has a Son
The Son of God is not only mentioned in messianic prophecies but there is also specific reference to God’s Son in the Tanakh (Old Testament). Psalm 2 is a messianic psalm and includes “I will declare the decree: the Lord has said to Me, You are My Son, today I have begotten You (v7)”and in verse 12 “Kiss the Son lest He be angry, and you perish in the way, when His wrath is kindled but a little. Blessed are all those who put their trust in Him.”
Proverbs 30:4 provides several rhetorical questions and the last one clearly tells us something about the Godhead. ‘Who has ascended into heaven, or descended? Who has gathered the wind in His fists? Who has bound the waters in a garment? Who has established all the ends of the earth? What is His name, and what is His Son’s name if you know?’
Isaiah 9:6-7 states that the Son will rule upon the throne of David. ‘For unto us a Child is born, unto us a Son is given; and the government will be upon His shoulder. And His name will be called Wonderful Counsellor, Mighty God, Everlasting Father, Prince of peace. Of the increase of His government and peace there will be no end, upon the throne of David and over his kingdom, to order it and establish it with judgement and justice from that time forward, even forever. The zeal of the Lord of hosts will perform this.’
The Angel of the Lord
There are a number of instances where the Angel of the Lord appears or receives worship and the recipient is amazed that they have seen God and survived (Genesis 22:11; Exodus 3:2-6; Judges 6:22; 13:22-23). That was Yeshua (Jesus) in preincarnate form. Also, consider who it was that was walking with Adam and Eve in the garden of Eden, who wrestled with Jacob and who was the fourth Man in the fiery furnace with Daniel’s friends?
References of One God in three Persons together
There are several occurrences in Isaiah where the three Persons of the Trinity are mentioned. The second reference shows that the Son has always existed alongside the Lord God and His Spirit. Ibn Ezra thought that decree was made to His Spirit as [i]relating to angels, though this doesn’t account for the “me” in that context as an uncreated being sent by the Lord God and the Spirit.
“Behold! My Servant whom I uphold,
My Elect One in whom My soul delights!
I have put My Spirit upon Him;
He will bring forth justice to the Gentiles (Isaiah 42:1).”
“Come near to Me, hear this:
I have not spoken in secret from the beginning;
From the time that it was, I was there.
And now the Lord God and His Spirit
Have sent Me (Isaiah 48:16).”
“The Spirit of the Lord God is upon Me,
Because the Lord has anointed Me
To preach good tidings to the poor;
He has sent Me to heal the brokenhearted,
To proclaim liberty to the captives,
And the opening of the prison to those who are bound (Isaiah 61:1);”
But what about the Shema?
Deuteronomy 6:4 is central to Judaism. “Hear O Israel. The Lord our God, the Lord is one.” How does this statement harmonise with the Scriptures mentioned above? The word for ‘one’ in this verse is ‘echad’ and is vital for interpreting this passage. Though it can be used of the number one it is also frequently used in terms of a compound or unified one.
To cite some examples, ‘God called the light Day, and the darkness He called Night. So the evening and the morning were the first day (Genesis 1:5).’ The Day is made up of day and night though it is one day.
When God brought Eve to Adam, He said, “Therefore a man shall leave his father and mother and be joined to his wife, and they shall become one flesh (Genesis 2:24).” Adam and Eve are two people, yet they became one together.
When worship was restored in Jerusalem in the book of Ezra, ‘And when the seventh month had come, and the children of Israel were in the cities, the people gathered together as one man to Jerusalem (Ezra 3:1).’ The people are many though they united as one (echad).
When Ezekiel prophesied concerning Judah and the Children of Israel, he said “Then join them one to another for yourself into one stick, and they will become one in your hand (Ezekiel 37:17).” Though the northern and southern kingdom are separated, they will be joined and become one.
Although Maimonides states that there is one (yachid) God, this is undoubtedly a reaction to unbiblical “Christian” beliefs that gave Jewish people the impression that Christians worshipped three gods.[ii] Deuteronomy 6:4 tells us that God is one (echad) and this agrees with the rest of Scripture.
A couple of references concerning Yachid
Yachid is used in Genesis 22:12 regarding the Angel of the Lord recognising that Abraham feared God and he hadn’t withheld his only son from him. This itself is a type and foreshadowing of when Yeshua, God’s only begotten Son would be given to make atonement for sin. Another reference to yachid is Zechariah 12:10 about the inhabitants of the house of David and the house of Jerusalem mourning for his only son, and grieve for Him as one grieves for a firstborn. This again speaks of Messiah Yeshua who was pierced to make atonement (c.f. Psalm 22:16; Isaiah 53:5; c.f. John 19:31-37; Revelation 1:7).
The Trinity in the Brit Hadasha (New Testament)
Until now we have looked only at the Tanakh to provide support for the doctrine of the Trinity. This demonstrates that the New Testament isn’t teaching about God in a way that is contrary to the Old Testament. It is important to show equally how the New Testament affirms this view. Yeshua was baptised and thereby identified Himself with His Father. Notice the cooperation of the three Persons of the Trinity present at His baptism in Matthew 3:16-17.
“When He had been baptized, Jesus came up immediately from the water; and behold, the heavens were opened to Him, and He saw the Spirit of God descending like a dove and alighting upon Him. And suddenly a voice came from heaven, saying, “This is My beloved Son, in whom I am well pleased.”
Again in John 14:26, Jesus explains that the Holy Spirit will be sent to teach his disciples all things and we see the cooperative functions of the Godhead.
“But the Helper, the Holy Spirit, whom the Father will send in My name, He will teach you all things, and bring to your remembrance all things that I said to you.”
Finally in Matthew 28:19-20 at the end of that Gospel Jesus commands them to make disciples not just in His name, or His Father’s name but in the name of the Father, Son and Holy Spirit.
“Go therefore and make disciples of all the nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, teaching them to observe all things that I have commanded you; and lo, I am with you always, even to the end of the age.” Amen.
[i] Commentary of Ibn Ezra on Isaiah https://books.google.co.uk/books?id=z9UMAAAAIAAJ&printsec=frontcover&redir_esc=y#v=onepage&q&f=false
[ii] Michael L. Brown Answering Jewish Objections to Jesus Volume 2 (Baker: Grand Rapids; 2000), p4