Scripture and the Holy Spirit
There was strong recognition before canonization as to what was scripture and what awasn't in the the second century.
I don't beleive you understand history as you claim.
History of The Trinity
The growth of the doctrine of a triune God, is briefly but plainly, set forth in the following facts:
A.D. 29 Jesus said, "The Lord our God is one Lord" (Mark 12:29).
A.D. 57 Paul said, "To us there is but one God" (1 Cor. 8:6).
A.D. 120 "Apostles' Creed": "I believe in God the Father".
A.D. 150 Justin Martyr, introduces Greek Philosophy.
A.D. 170 The word "Trias", appears first in Christian literature.
A.D. 200. "Trinitas" is first introduced by Tertullian.
A.D. 280 Origen, opposes prayers to Christ.
A.D. 260 Sabellius: "Father, Son and Holy Ghost are three names for the same God".
A.D. 325 "Nicene Creed" afflrms Christ to be "Very God of Very God".
A.D. 381. Council of Constantinople invents "Three persons in One God".
A.D. 388 Emperor Theodosius threatens punishment to all who won't worship the Trinity.
The Athanasian Creed
According to the "Athanasian Creed", "Whosoever will be saved; before all things it is necessary that he hold the Catholic faith. Which faith except every one do keep-whole and undefiled: without doubt he shall perish everlastingly. And the Catholic faith is this: "That we worship one God in Trinity, and Trinity in Unity; Neither confounding the Persons: nor dividing the Substance. For there is one Person of the Father, another of the Son, and of the Holy Ghost. But the Godhead of the Father, of the Son, and of the Holy Ghost is all one: the Glory equal, the Majesty co-eternal. Such as the Father is, such is the Son: and such is the Holy Ghost. The Father uncreate, the Son uncreate: and the Holy Ghost uncreate. The Father incomprehensible, the Son incomprehensible: and the Holy Ghost incomprehensible. The Father eternal, the Son eternal: and the Holy Ghost eternal. And yet they are not three Eternals: but one Eternal. As also there are not three incomprehensibles, nor three uncreated; but one uncreated, and one incomprehensible. So likewise the Father is Almighty, the Son Almighty: and the Holy Ghost Almighty. And yet they are not three Almighties: but one Almighty. So the Father is God, the Son is God: and the Holy Ghost is God. And yet there are not three Gods: but one God. So likewise the Father is Lord, the Son is Lord: and the Holy Ghost is Lord. And yet not three Lords: but one Lord". And, it goes on to say: "And in this Trinity none is afore, or after another: none is greater, or less than another: But the whole three Persons are co-eternal together: and co-equal. So that in all things, as is aforesaid: the Unity in Trinity, and the Trinity in Unity is to be worshipped. He therefore that will be saved: must thus think of the Trinity".