Despite what the Watchtower teaches, the origin of the Trinity is GOD'S WORD!
They deny that there is evidence that the Trinity was taught in prior to the 4th century (see "answer" below me), but there is proof to the contrary.
Once proof is provided, JWs back-pedal and claim that "Oh, that must have been part of the 'apostacy' that Paul warned about," never stopping to consider the possiblity that its the other way around...
"I marvel that ye are so soon removed from him that called you into the grace of Christ unto another gospel: Which is not another; but there be some that trouble you, and would pervert the gospel of Christ.
But though we, or an angel from heaven, preach any other gospel unto you than that which we have preached unto you, let him be accursed. As we said before, so say I now again, if any man preach any other gospel unto you than that ye have received, let him be accursed." Galatians 1:6-9
As for the argument that there were triadic gods predating the first century, one could just as easily argue the details of Jesus' birth and mission were stolen from pagan religions.
But the truth is that Satan had knowledge of the Nature of God and His plan for redemption and had been working on perverting the true message since "the fall of man."
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Ignatius and Polycarp, students of the Apostle John both are documented as believing Jesus is God in the flesh (which blows the NWT version of John 1:1 right in the trash) Further, they have hinted at the trinity since the first century without it being called that until about 200 AD. Regardless, the Trinity was certainly a belief well before the 4th century.
Ignatius (died 117 AD)
The Epistle of Ignatius to the Magnesians, Chap. XIII
Study, therefore, to be established in the doctrines of the Lord and the apostles, that so all things, whatsoever ye do, may prosper both in the flesh and spirit; in faith and love; in the Son, and in the Father, and in the Spirit; in the beginning and in the end; with your most admirable bishop, and the well-compacted spiritual crown of your presbytery, and the deacons who are according to God. Be ye subject to the bishop, and to one another, as Jesus Christ to the Father, according to the flesh, and the apostles to Christ, and to the Father, and to the Spirit; that so there may be a union both fleshly and spiritual. (short version)
The Epistle of Ignatius to the Magnesians, chap.VI
For they alienate Christ from the Father, and the law from Christ. They also calumniate His being born of the Virgin; they are ashamed of His cross; they deny His passion; and they do not believe His resurrection. They introduce God as a Being unknown; they suppose Christ to be unbegotten; and as to the Spirit, they do not admit that He exists. Some of them say that the Son is a mere man, and that the Father, Son and Holy Spirit are but the same person, and that the creation is the work of God, not by Christ, but by some other strange power.
The Epistle of Ignatius to the Philadelphians, Chap. VI
If any one says there is one God, and also confesses Christ Jesus, but thinks the Lord to be a mere man, and not the only-begotten God and Wisdom, and the Word of God, and deems Him to consist merely of a soul and body, such an one is a serpent, that preaches deceit and error for the destruction of men...If any one confesses the Father, and the Son, and the Holy Ghost, and praises the creation, but calls the incarnation merely an appearance, and is ashamed of the passion, such an one has denied the faith, not less than the Jews who killed Christ. If any one confesses these things, and that God the Word did dwell in a human body, being within it as the Word, even as the soul also is in the body, because it was God that inhabited it, and not a human soul, but affirms that unlawful unions are a good thing, and places the highest happiness in pleasure, as does the man who is falsely called a Nicolaitan, this person can neither be a lover of God, nor a lover of Christ, but is a corrupter of his own flesh, and therefore void of the Holy Spirit, and a stranger to Christ. (long version)
50 AD The Huleatt Manuscript
* 50 AD The Huleatt Manuscript "She poured it [the perfume] over his [Jesus'] hair when he sat at the table. But, when the disciples saw it, they were indignant. . . . God, aware of this, said to them: 'Why do you trouble this woman? She has done [a beautiful thing for me.] . . . Then one of the Twelve, who was called Judas Iscariot, went to the chief priest and said, 'What will you give me for my work?' [Matt. 26:7-15]" (Huleatt fragments 1-3).
150 AD Justin Martyr
* 150 AD Justin Martyr "The Father of the universe has a Son, who also being the first begotten Word of God,
* is even God." (Justin Martyr, First Apology, ch 63) 150 AD Justin Martyr "Christ is called both God and Lord of hosts." (Dialogue with Trypho, ch, 36)
* 150 AD Justin Martyr "Moreover, in the diapsalm of the forty-sixth Psalm, reference is thus made to Christ: 'God went up with a shout, the Lord with the sound of a trumpet." (Dialogue with Trypho, ch 37)
* 150 AD Justin Martyr quotes Hebrews 1:8 to prove the Deity of Christ. "Thy throne, O God, is forever and ever." (Dialogue with Trypho, ch 56)
* 150 AD Justin Martyr "Therefore these words testify explicitly that He [Christ] is witnessed to by Him who established these things, as deserving to be worshipped, as God and as Christ." - Dialogue with Trypho, ch. 63.
* 150 AD Justin Martyr in Chap. LXVI. He (Justin) Proves From Isaiah That God Was Born From A Virgin. (Chapter Title, Chap. LXVI)
* 150 AD Justin Martyr "And Trypho said, "You endeavor to prove an incredible and well-nigh impossible thing;[namely], that God endured to be born and become man...some Scriptures which we mention, and which expressly prove that Christ was to suffer, to be worshipped, and [to be called] God, and which I have already recited to you, do refer indeed to Christ." (Dialogue with Trypho, ch 68)
# 150 AD Justin Martyr "But both Him, and the Son (who came forth from Him and taught us these things, and the host of the other good angels who follow and are made like to Him), and the prophetic Spirit,we worship and adore." (Justin Martyr, First Apology, ch 6) Notice what else Justin say: "Worship God alone." (Justin Martyr, First Apology, ch 16) "Whence to God alone we render worship." (Justin Martyr, First Apology, ch 17)
150 AD Polycarp of Smyrna
* 150 AD Polycarp of Smyrna "I praise you for all things, I bless you, I glorify you, along with the everlasting and heavenly Jesus Christ, your beloved Son, with whom, to you and the Holy Spirit, be glory both now and to all coming ages. Amen" (Martyrdom of Polycarp 14).
170 AD Tatian the Syrian
* 170 AD Tatian the Syrian "We are not playing the fool, you Greeks, nor do we talk nonsense, when we report that God was born in the form of a man" (Address to the Greeks 21).
# 180 AD Irenaeus "
# But the Son, eternally co-existing with the Father, from of old, yea, from the beginning, always reveals the Father to Angels, Archangels, Powers, Virtues..." (Against Heresies, Book II, ch. 30, section 9) 180 AD Irenaeus "Christ Jesus is our Lord, and God, and Savior, and King." (Against Heresies, Book I, ch. 10, section 1) 180 AD Irenaeus "For I have shown from the scriptures, that no one of the sons of Adam is as to everything, and absolutely, called God, or named Lord. But that He is Himself in His own right, beyond all men who ever lived, God, and Lord, and King Eternal, and the Incarnate Word, proclaimed by all the prophets, the apostles, and by the Spirit Himself, may be seen by all who have attained to even a small portion of the truth. Now, the scriptures would not have testified these things of Him, if, like others, He had been a mere man. (Irenaeus Against Heresies, chapter xix.2)
# 180 AD Irenaeus "God, then, was made man, and the Lord did Himself save us, giving us the token of the Virgin." (Against Heresies, Book III, ch. 21, section 1) 180 AD Irenaeus "Christ Himself, therefore, together with the Father,
# is the God of the living, who spake to Moses, and who was also manifested to the fathers." (Against Heresies, Book IV, ch. 5, section 2) 180 AD Irenaeus "And for this reason all spake with Christ when He was present [upon earth], and they named Him God." (Against Heresies, Book IV, ch.6, section 6)
# 190 AD Clement Of Alexandria [note:Clement NEVER calls Jesus a creature.] "There was then, a Word importing an unbeginning eternity; as also the Word itself, that is, the Son of God, who being, by equality of substance, one with the Father, is eternal and uncreated." (Fragments, Part I, section III)
# 190 AD Clement Of Alexandria "I understand nothing else than the Holy Trinity to be meant; for the third is the Holy Spirit, and the Son is the second, by whom all things were made according to the will of the Father." (Stromata, Book V, ch. 14) 190 AD Clement Of Alexandria "When [John] says: 'What was from the beginning [1 John 1:1],' he touches upon the generation without beginning of the Son,who is co-equal with the Father. 'Was,' therefore, is indicative of an eternity without a beginning, just as the Word Himself, that is the Son, being one with the Father in regard to equality of substance, is eternal and uncreated. That the word always existed is signified by the saying: 'In the beginning was the Word' [John 1:1]." .... ran out of space, continued here: https://answersrip.com/question/index?qid=20080703231