[Note: I am not promoting a religion, a church system, nor a set of beliefs. I am merely reporting history as I find it.]
The early, Ante-Nicene Church Fathers spent much time fighting heresies. Their writings are recognized by all Christian denominations. Even the Watchtower Society accepts them, but they dishonestly do not quote the portions which hurt their non-Trinitarian doctrine. Later on I will post material which shows how the Watchtower Trinity brochure, "Should You Believe in the Trinity?" used deception and dishonest practices.
Year 150 AD, Polycarp of Smyrna, a student of the Apostle John said this regarding the Father, the Son, and the Holy Spirit: "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).
It is fascinating to note how Polycarp is glorifying Jesus (who he says is everlasting) along with the Father, and the Holy Spirit. Though the word "Trinity" was not used, clearly, Polycarp, as a first generation Christian appears to believe in the concept.
Year 160 AD, Mathetes "[The Father] sent the Word that he might be manifested to the world . . . This is he who was from the beginning, who appeared as if new, and was found old . . . This is he who, being from everlasting, is today called the Son" (Letter to Diognetus 11).
Mathetes, like Polycarp, declares Jesus to be "from everlasting" an expression that means he has no beginning, and thus part of God.
Year 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).
Year 177 AD, Melito of Sardis "It is no way necessary in dealing with persons of intelligence to adduce the actions of Christ after his baptism as proof that his soul and his body, his human nature, were like ours, real and not phantasmal. The activities of Christ after his baptism, and especially his miracles, gave indication and assurance to the world of the deity hidden in his flesh. Being God and likewise perfect man, he gave positive indications of his two natures: of his deity, by the miracles during the three years following after his baptism, of his humanity, in the thirty years which came before his baptism, during which, by reason of his condition according to the flesh, he concealed the signs of his deity, although he was the true God existing before the ages" (Fragment in Anastasius of Sinai's The Guide 13).
Year 180 AD, Irenaeus, student of Polycarp: "His own hands. For with Him were always present the Word and Wisdom, the Son and the Spirit, by whom and in whom, freely and spontaneously, He made all things, to whom also He speaks, saying, "Let Us make man after Our image and likeness; " [Gen. 1:26]" (Against Heresies 4:20:1).
Note: So, now we see the "Spirit" introduced as always with God as is Jesus. The Fathers mostly dealt with Jesus divinity because he was the most attacked by various heresies.
Year 180 AD, Irenaeus "Proofs From The Apostolic Writings, That Jesus Christ Was One And The Same, The Only Begotten Son Of God, Perfect God And Perfect Man
." (Against Heresies, Book III, ch. 16, Chapter Title)
Now, we have St. Clement of Alexandria. He was Bishop of the Church founded by the Bible writer, St. Mark. St. Clement was a contemporary of Irenaeus, specifically detailed the Trinity formula, and used the word Trinity in the year 190 AD. This predates the Council of Nicea by 135 years, and is only about 90 years after the Apostle John and St. Ignatius death. This is hardly enough time for a false doctrine to take over the early church.
Year 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)
Year 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)
Year 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]." (fragment in Eusebius History, Bk 6 Ch 14; Jurgens, p. 188)
Then there is St. Justin Martyr, who likewise detailed the divinity of Jesus in no uncertain terms in his fight against heresies, as most all the early Church Fathers did. I have literally dozens of cases where he was explicitly clear, and like St. Irenaeus and others spoke of the Holy Spirit as a person.
The historical evidence is that the early Christians believed in what we would call the Trinity, and it was non-Trinitarian forces that were constantly developing weird new ideas to influence the Church, but they all eventually failed. Again, this clear teaching being taught by 170 to 190 AD is too soon after the death of the Apostle John and the first disiples, such as St. Ignatius, St. Polycarp, and St. Irenaeus, for a generalized apostasy to have allowed such a doctrine to be fully developed.
It seems to me that the Watchtower Society got yet another one wrong again.
Jim Whitney