Did the apostles believe God was a Trinity?

Polycarp affirms the Trinity

Polycarp affirms the trinity.¹ This is relevant because Polycarp's teachings matched that of the apostles.

• Polycarp (writting in c. AD 110-140): “May the God and Father of our Lord Jesus Christ, and the eternal High Priest Jesus Christ Himself, the Son of God, help you to grow in faith and truth, in unfailing gentleness and the avoidance of all anger, in patience and forbearance, and in calmness and purity. To you, and to ourselves as well, and to all those under heaven who shall one day come to believe in our Lord Jesus Christ and in His Father who raised Him from the dead, may He grant part and portion among His saints.” [Polycarp to the Phillipians Section 12]

Clement affirms the Trinity

Clement affirms the trinity. This is relevant because Clement's teachings matched that of the apostles.¹

Consider three reasons to think their teachings largely matched:
• Irenaus reports that they matched.
Irenaeus (writing in c. AD 180): “The blessed apostles, then, having founded and built up the Church, committed into the hands of Linus the office of the episcopate. Of this Linus, Paul makes mention in the Epistles to Timothy. To him succeeded Anacletus; and after him, in the third place from the apostles, Clement was allotted the bishopric. This man, as he had seen the blessed apostles, and had been conversant with them, might be said to have the preaching of the apostles still echoing [in his ears], and their traditions before his eyes. Nor was he alone [in this], for there were many still remaining who had received instructions from the apostles. In the time of this Clement, no small dissension having occurred among the brethren at Corinth, the church in Rome despatched a most powerful letter to the Corinthians, exhorting them to peace, renewing their faith, and declaring the tradition which it had lately received from the apostles, proclaiming the one God, omnipotent, the Maker of heaven and earth, the Creator of man […][Against Heresies, Vol. 3, Ch. 3]
• Clement was bishop of Rome. This is relevant because this is unlikely if Clement did not know the apostles.
• The Clement in Phillippians is Clement of Rome.² This is relevant because it indicates Clement's teachings matched Paul's (who wrote Phillipians), and this in turn is relevant because Paul's teachings matched the apostles. The reason to think the Clement in Phillians is the Clement of Rome is the following.
The reason to think the Clement in Phillipians is Clement of Rome is as follows: both are associated with members of Caesar's houshold.
• Clement of Rome is plausibly associated with members of Caesar's household (See names characteristic of household:
• Clement (writing in AD 96): “Make haste and send our messengers, Claudius Ephebus, Valerius Vito, and Fortunatus, back to us in peace and joy…” [Epistle to the Corinthians Section 65]).
“As Nero belonged to the Claudian family, and his consort Messalina to the Valerian, several instances have been found of the two names Claudius (or Claudia) and Valerius (or Valeria) occurring in combination with reference to servants in the royal employment. Possibly this is the case here. It has even been conjectured that these two elderly envoys may have been among the members of 'Caesar's household' mentioned by St Paul in Philippians iv, 22.”

• Clement in Phillipians is associated with members of Caesar's household (Philippians 4:22 “All the saints greet you, especially those of Caesar's household.”)

Ignatius affirm the Trinity

Ignatius affirms the trinity.¹ This is relevant because Ignatius's teachings matched that of the apostles.²

Ignatius (writing in AD 107): “There is only one Physician -- Very flesh, yet Spirit too; Uncreated, and yet born; God-and-Man in One agreed, Very-Life-in-Death indeed, Fruit of God and Mary’s seed; At once impassible and torn By pain and suffering here below; Jesus Christ, whom as our Lord we know.”[Epistle to Ephesians Section 7]
Ignatius (writing in AD 107): “Deaf as stones you were: yes, stones for the Father’s Temple, stones trimmed ready for God to build with, hoisted up by the derick of Jesus Christ (the cross) with the Holy Spirit for a cable; your faith being the winch that draws you to God, up the ramp of love.” [Epistle to Ephesians Section 9,]
Ignatius (writing in AD 107): “As for me, my spirit is now all humble devotion to the Cross: the Cross which so greatly offends the unbelievers, but is salvation and eternal life to us. Where is your wise man now, or your subtle debater? Where are the fine words of our so-called intellectuals? Under the divine dispensation, Jesus Christ our God was conceived by Mary of the seed of David and of the Spirit of God; He was born, and He submitted to baptism, so that by His passion He might sanctify water.” [Epistle to Ephesians Section 18]
Ignatius (writing in AD 107): “Glory be to Jesus Christ, the Divine One who has gifted you with such wisdom. I have seen how immovably settled in faith you are; nailed body and soul, as it were, to the cross of the Lord Jesus Christ, and rooted and grounded in love by His blood. You hold the firmest convictions about our Lord; believing Him to be truly of David’s line in His manhood, yet Son of God by the Divine will and power, truly born of a Virgin; baptized by John for His fulfilling of all righteousness…”
There are two reasons to think Ignatius's teachings matched the apostles:
• Ignatius's teachings match Polycarp's. And this is relevant because [Polycarp's teachings matched the apostles].
• Ignatius was a disciple of John. (He was a close friend with Polycarp, who was a disciple of John). And this is relevant becase John was an apostle.

Mathetes affirms the Trinity

[Put under: Apostles believed Jesus was God]
Mathetes affirms that Jesus is Divine.¹ This is relevant becaues Mathetes's teaching matched the apostles.²

Mathetes (writing between AD 130-2nd century): “How can anyone, who has been rightly taught and learnt to love the Word, not wish to be told the precise nature of the revelations which that Word so openly made to his disciples? Visibly present among them, the Word made His disclosures to them in the plainest of language; though unrecognized by the unbelieving, He disclosed without reserve to the disciples; and because they were reckoned faithful by Him, they came to know the mysteries of God. That was the purpose for which God sent the Word to be manifested to the world. He was despised by the Chosen people, but preached by the Apostles and believed in by the Gentiles. Though He has existed since the beginning, He came as one appearing newly; though we know Him to be from old, He is born ever anew in the hearts of His saints. This is He who is from everlasting, this is He who is accounted this day a Son. Through Him, the Church is enriched; abounding grace is multiplied among the saints, furnishing understanding, revealing mysteries, proclaiming times and seasons, and rejoicing over the faithful believers – the grace which is granted to every seeker who does not violate the vows of faith, or transgress the bounds fixed by the Fathers.” [Epistle to Diognetus, Section 11]
[Immediately after the quote above] Mathetes (writing between AD 130-2nd century): “Although I am an instructor of the Gentiles now, I was a pupil of the Apostles once; and what was delivered to me then, I now minister faithfully to students of the truth.” [Epistle to Diognetus, Section 11]

Paul affirms the Trinity

Paul affirms the God is a Trinity. This is relevant because [Paul's teachings matched that of the apostles].