According to Trinitarians, were/are some Jews Trinitarians? Who is this "Father" - the Creator spoken of throughout the Old Testament?

The Bible, meaning New and Old Testament, describes three aspects of God as Father.

Universal/Familial
¹⁴ For this reason I bow my knees before the Father, ¹⁵ from whom every family in heaven and on earth is named (Ephesians 3 ESV)

Individual/Personal
And because you are sons, God has sent the Spirit of his Son into our hearts, crying, “Abba! Father!” (Galatians 4:6; also Romans 8:15)

Unique
This was why the Jews were seeking all the more to kill him, because not only was he breaking the Sabbath, but he was even calling God his own Father, making himself equal with God. (John 5:18)

While the familial is found in the Old Testament, it was not understood as universal until the New Testament. Claiming this was understood as such before the New Testament is an anachronistic application of the progressive revelation of God. The Old Testament was given to the Jewish people. All of the OP's verses speak of God as Father of the Jewish people.¹They are God's chosen people; YHVH calls Israel His son (Hosea 11:1). There is no evidence the Jewish people believed one who was not a Jew could call YHVH, "Father." As Paul says, non-Jews were alienated from the commonwealth of Israel and strangers to the covenants of promise, having no hope and without God (Ephesians 2:12).

Moreover, there is no basis to claim the Jews understood their relationship to YHVH was a result of creation. Yes Judaism recognizes one God as Creator, but Jews call YHVH Father because they alone were chosen from among all which God created.

The New Testament revelation is God is also the God of the Gentiles:

²⁸ For we hold that one is justified by faith apart from works of the law. ²⁹ Or is God the God of Jews only? Is he not the God of Gentiles also? Yes, of Gentiles also, ³⁰ since God is one—who will justify the circumcised by faith and the uncircumcised through faith. (Romans 3)

It is Paul who corrects Judaism's narrow understanding of God and Father. Yes the Jews were chosen. Yet neither that action, nor Gentile ignorance, nor rebellion, nor outright rejection altered the fact God has always been, and always will be the God of both Jew and Gentile.

The New Testament reveals that Gentiles could God, Father. But this was not a consequence of being brought out of Egypt, or due to the obedience of Abraham. It was the person of Jesus Christ who gave any person the right to be reborn as children of God. It is only the reborn person says Abba, Father. The familial becomes universal, only when all physical ancestry is replaced with rebirth by the will of God. It is universal only because it is available from God to every individual.

Finally, there is the unique sense of Father. Only Jesus Christ can correctly say My Father. He is uniquely the only-begotten. No other has the same relationship to the Father as does He. This claim is why the Jews sought to kill Him.

The phrase calling God His own Father is πατέρα ἴδιον ἔλεγεν τὸν θεόν. The key word is ἴδιον, idios. The meaning of idios as Jesus uses it is private. The Jews might call YHVH Father since He called Israel His son, or because they knew themselves as chosen people. But Jesus claimed a unique relationship: He could say My Father because He came from the One the Jews knew as their Father. It is the claim of exclusivity which necessarily means equality with God for which the Jews sought to kill Him.

Summary
The Trinitarian understanding of God can be compared to that of the Old Testament:

YHVH ---> Abraham ---> Abraham's descendants
The Father  ----> Jesus -----> Jesus' descendants

Where Abraham's descendants call YHVH, Father, Christians says Abba Father.

The Jews know only of Father. The person reborn knows both Abba and Father. The equality inherent in the repetition in the Christian confession simply affirms what Jesus said of Himself, I and the Father are one.

_{1. Have we not all one Father? Has not one God created us? Why do we deal treacherously with one another By profaning the covenant of the fathers? Malachi is clearly speaking about Jews only: those who have the covenant of the fathers. But now, O YHWH, You are our Father; We are the clay, and You our potter; And all we are the work of Your hand. We are the clay; not the dust of the earth which made man, but we only those who have been chosen. Doubtless You are our Father, Though Abraham was ignorant of us, And Israel does not acknowledge us. You, O YHWH, are our Father; Our Redeemer from Everlasting is Your name. Abraham and Israel are not understood as they are in the NT. This is speaking only of Jews. Do you thus deal with YHWH, O foolish and unwise people? Is He not your Father, who bought you? Has He not made you and established you? At the time this was written who did YHVH buy? Only the Jews. All people were bought at the cross. The passage in John should be put in context. First the Jews claimed Abraham was their father (8:39) only after Jesus refuted their claim did they fall back to God is our Father. Moreover, it is clear from their statements, they do not understand this as universal applying to all people. We are not born of fornication... means those who were [and they are accusing Jesus of being illegitimate and a Samaritan (8:48)] do not have God as Father.}

Most Israelites/Jews in the Old Testament period were not saved. Most, if they sought salvation at all, sought it by their own righteousness. Most thought salvation came by obedience to the law of Moses. And so most had no faith in a coming Saviour to deal with sin.. they didn't need one, their sins were not so bad as to need a Saviour. Likewise most had no experience of the Holy Spirit who is given when we believe on a divine Saviour to take away sin. Unbelieving Jews when they spoke of the Father had no belief in a Triune God. Malachi himself believed in a Triune God but he is not using the term Father in Mal 2:10 in a Trinitarian way. Neither are the Jews in John 8:41.

But some Israelites/Jews in OT era were saved. These believed in a coming divine Saviour who would be also human. So Job makes clear he believes in a coming Kinsman-redeemer (i.e. human) who would be God, he will see God with his own eyes; that is, God would appear in physical form (Job 19:25-27). All the saints of the OT believed in a coming divine Saviour. And in some places it is clear they had experience of and acknowledged the existence of God's Holy Spirit. So David could say "Take not thy Holy Spirit from me", Psalm 51:11.

It is true the Holy Spirit was poured out in great measure after Jesus was ascended into heaven (John 7:39). But it is not true there was no experience of the Holy Spirit before our Lord was glorified. Without the Holy Spirit's indwelling you cannot be saved (Romans 8:9).

God as a human / a nation's father

In his answer, Nigel already covered the Biblical basis for the fatherhood of each human being:

• bodily & existentially ("out of the dust from the ground", Gen 2:7a) and
• spiritually (receiving "breath of life", Gen 2:7b) as being stamped with God's image (which includes in it our conscience and the capacity to know and love God).

This is the common heritage of all humanity: God being every human being's "father".

In addition, the Jews (as biological descendants of Abraham) correctly understood God as the father of Israel who made a covenant with them (Hosea 1:1)

In both verses you cited, the prophet Malachi and the Jesus (in his office as prophet), confronted the Jews that they have not acted faithfully in their covenant with God:

• profaning the Temple by sacrificing to foreign God (Mal 1-2)
• by being driven to sinful acts due to following their sinful desires, shown by their refusal to believe Jesus's words and by their trying to kill God's prophet (John 8:34-47)

Before Jesus came, the Jews understood this God as the "Most High God" (Gen 14:20) above all other gods (monolatry) which over the OT history developed into the belief that this Most High God has ultimate power over other gods, forces of nature, the realm of the dead (the Pharisees believed the resurrection of the body), and even time & space & psyche that no man/woman can hide from (Ps 139).

THE ABOVE IS THE JEW'S ANSWER to your question "who is this father they speak of*.

Trinitarian formula as deeper insight into Israel's God

After Jesus came, we have deeper insight to Israel's God who revealed himself in Jesus, which the apostles and the NT writers understood from his words, his teachings, and his deeds as showing Jesus not only as prophet (Deut 18:15), as king (Eze 37:24-27, Zech 9:9), as messiah (Isa 9:6-7), and as Son of Man (Daniel 7:13-14), but also as the incarnation of Israel's God into 100% human who previously was already somewhat present in the Holy of Holies, though less fully than in Jesus. In Jesus God declares that we can obtain the forgiveness of sin, peace, guidance & wisdom, spiritual water & bread (to nourish our spirit), and especially power to overcome sin, if we repent and identify ourselves with Jesus's death and resurrection in baptism (i.e. born again, John 3:5-8).

Trinitarians believe that Jesus can give us all the above because he IS "the human being of God" who truly walked as God along the shores of Galilee to demonstrate that God is truly WITH US in solidarity in human weakness and frailty. Jesus is Israel's God in bodily form, from whom all grace must come, channeled through Jesus to us as the vine to the branches (John 15:4-5). If Jesus were mere human, it would be preposterous. If Jesus were mere super creature greater than angel, he would still owe his existence to this supreme God, which would risk creating idolatry just like Israels were tempted to worship foreign gods they perceived to be greater than YHWH.

In the NT, Jesus is described as the "Son of God" in a sense MORE than human beings are "sons of God" and MORE than David as "Son of God" (as King). Since Christians believe that the NT authors were inspired when they wrote as they processed their encounter with Jesus (either in person or through the testimony of others who did), Trinitarians then tried to find a good formula / concept to distill in proposition form what NT writers wrote as letters, narratives, etc. Trinitarians do NOT add to the revelation, but through the formulas they used proposition form to indicate truths of the nature of Israel's God as well as to carve out a boundary to exclude errors regarding the nature of Jesus and of God.

Thus, through the early centuries, Trinitarians laboriously came up with a formula preserved in the creeds which are respectful, continuous, and downstream (in terms of prophetic content) from the Bible, that as "Son of God" Jesus is the enfleshment (the adding-on of the bodily human nature) of the "eternally generated" Word from the Father (the Word being spiritual, the second person of the Trinity). It is very important to understand that

• this Father-Son relationship implied by this "eternal generation" is NOT exactly the same as human father to human son relationship. It is an imperfect analogy to describe the immanent relationship within the Godhead. This is done to preserve the divinity of Jesus, so that the practical benefit for us described above makes sense (all grace must come from God directly, only God can transform us to be like Him). It is also to assert that the human Jesus is ONE IN BEING with Israel's God, thus preserving monotheism when we worship Jesus.
• Jesus as human being has another Father-son relationship (in his human nature) with Israel's God which (unlike the eternal generation above) we can fully imitate by grace as fellow human beings, when Jesus prayed to God and depended on God, for example. In this regard, Jesus can truly become our model human being. He is a servant leader (washing the disciples' feet). He forgives enemies with mercy. He obeys secular government when they rule consistent with God's laws. He lays down his life for his friends according to his mission. He is a friend to the downtrodden and social outcast. He is guided and empowered by the Holy Spirit. He obeys his conscience without falling into temptation. Etc.

THE ABOVE SHOWS FURTHER INSIGHT OF ISRAEL'S GOD INNER NATURE understood from the Trinitarian's perspective when the early church fathers processed further the NT records of the Apostles's encounter with Jesus. The resulting understanding IMPROVES ON the Jew's understanding of Israel's God by seeing Jesus not as a separate being, but as the SAME being conceived as God's Son (eternally generated) and as Second Adam (model human being into which we are being transformed by the power of the Trinitarian life infused to us when we are born again).

Conclusion

Since the Jews did not have this improved / deeper insight into Israel's God (because they understood Jesus as a separate being), their understanding of Israel's God as Father is not Trinitarian. Trinitarians "recast" (to use a programmer's term) the Jewish's understanding of Israel's God into 3 "subsistent relations" to whom we (as created beings) relate personally to this One Most High God in 3 hypostases:

• the Father (origination side of the eternal-generation relation) who is the subject prominently acting in the OT
• the Son (filiation side of the eternal-generation relation), who incarnated as Jesus in the NT but also made "cameo" appearances in the OT (as Lady Wisdom in Proverbs 8, for example)
• the Spirit (the spirated-love relation), who also made "cameo" appearances in the OT but more prominently now (since Pentecost) in the life of the church and inside each believer

P.S. (answers to objections)

Objection 1: All this language of hypostases, generation, and spiration reduces God into a concept

Answer 1: Theology uses concepts to describe God as best we can while asserting that we can never define God. Just as OT uses anthropomorphic language to describe a lot of God's actions and attitudes to us, Christian theologians use philosophical language to try to understand the inner nature of God as revealed more fully in the NT. Both are human analogies that we know to be inadequate to fully define God, but we use them to indicate truth and exclude errors so we can relate to the Biblical God better and discard other religions's concepts of God.

God is what He is, God does what He wants. He is ultimately mysterious but not unknowable or incomprehensible. Using concepts we can approach God in our thinking, although we cannot stop at thinking, but the thinking needs to result in AND TO ACCOMPANY (!!) acts of worship, acts of love, repentance, etc (since we are rational beings). We are not mere animals who do without thinking. Thus, we use concepts to understand and in turn, to love with understanding. Even the state of rapture / mysticism / beatific vision is described as beyond thinking, not against thinking. It is very hard to love someone we don't understand. Recounting actions and perceived emotions can only go so far; understanding helps us appreciate what animates the other person: their intention, motivation, and inner desires. Since God is spirit, Trinitarians use the psychological (spiritual) analogies of human knowing and loving to help us understand the immanent life of God as both are quintessential to the human spirit. The theory of subsistent relations, for example, enable us to appreciate the "inner heart" of God to understand his deeds better, as described in the Bible. Thus, philosophical language used reverently can complement the revealed anthropomorphic description of God in the Bible in a way that is consistent with Biblical discourse about God.

Furthermore, our mind uses concepts to direct our reason, will, and emotion toward our creator in a posture of worship, prayer, and thanksgiving and secondly, to motivate us to love ourselves and our neighbors better, as we cooperate with the grace given to us. In theology God is described analogously as faithful, loving, merciful, just, fatherly, etc. Those qualities are more concrete when seen through the lens of subsistent relations since at the core we are relational beings too. During the sanctification process our mind can better reflect and measure our own progress compared to how Jesus has those qualities in their fullness in his human nature as Jesus relate to the Father and as Jesus responds to the Holy Spirit. We want Jesus's Trinitarian life in our hearts as well, and Christianity teaches that God desires to give that life to us! It is our responsibility to receive, to understand (using concepts), and to let the indwelling Trinitarian life to be more influential in our earthly lifespan.

The verse quoted in Malachi specifically refers to God creating. The sense of 'father' in this specific verse is his fatherly attitude towards the creatures he created.

This thought is common throughout the Hebrew, Old Testament scriptures. The Jews, in the John 8 text, are referring to their natural generation from Abraham and his origin from Adam and Adam's origin from a creative act.

The revelation of the New Testament is the only begotten Son of the Father, not a matter of creation but a matter of begetting - a matter of life. 'The Life Eternal which was with the Father . . . . is manifested'.

And the revelation of the New Testament is the begetting of sons in the Holy Spirit, a 'birth from above', a 'birth again', a 'birth anew', a 'birth of water and of Spirit', a 'birth of God'.

Israel was a natural generation from father Abraham. The New Testament is a matter of a new birth, not of nature but of Spirit, a birth of eternal life from the Father by the Holy Spirit, in Christ.

No, Trinitarian doctrine does not view Jews (ancient or modern) as 'Trinitarian' just because they accept that God created their first human nature and has a fatherly regard for them as creatures.

Prior to the coming of the Son of God in humanity, the revelation was of Deity as such, but as yet not fully defined. Thus 'father' in the two texts above refers to Deity as a concept. But that label does not fully define the Deity.

The full revelation of the Father is only possible once the Son is revealed.