There was/is no "new belief" not supported by earlier works.
The last book considered part of the authentic inspired canon of the Holy Scriptures was Apocalipsis. It was finished writing and circulated in Christian congregations by the beginning of the second century. The existing Christian community after the death of John, its writer, no longer produced any new Scripture considered to be of divine inspiration. From that time on, the stage of formation of the basis of true Christianity had been completed, the one taught by Jesus and his followers anointed with holy spirit.
Should we believe that some new belief that was not supported by the earlier work of the holy spirit was true? Was the Christian community after that date authorized in any way to introduce new dogmas into the teachings that new Christians were to learn?
Dialogue of Justin, Philosopher and Martyr, with Trypho, a Jew. Chap. CXVI proceed now to show that the revelation made among your people in Babylon in the days of Jesus (Joshua) the priest, was an announcement of the things to be accomplished by our Priest, who is God, and Christ the Son of God the Father of all.
Chap. CXXVI. — The Various Names of Christ According to Both Natures. It Is Shown That He Is God, and Appeared to the Patriarchs.
“But if you knew, Trypho,” continued I, “who He is that is called at one time the Angel of great counsel,285 and a Man by Ezekiel, and like the Son of man by Daniel, and a Child by Isaiah, and Christ and God to be worshipped by David, and Christ and a Stone by many, and Wisdom by Solomon, and Joseph and Judah and a Star by Moses, and the East by Zechariah, and the Suffering One and Jacob and Israel by Isaiah again, and a Rod, and Flower, and Corner-Stone, and Son of God, you would not have blasphemer Him who has now come, and been born, and suffered, and ascended to heaven; who shall also come again, and then your twelve tribes shall mourn. For if you had understood what has been written by the prophets, you would not have denied that He was God, Son of the only, unbegotten, unutterable God.
Irenaeus [A.D. 120-202.] Against Heresies. Book I.Chap. VII. [Student of Polycarp, student of John]
5. Very properly, then, did he say, “In the beginning was the Word,” for He was in the Son; “and the Word was with God,” for He was the beginning; “and the Word was God,” of course, for that which is begotten of God is God. “
Irenaeus Against Heresies. Book III. Chap. XXI.
4. Therefore the Lord himself shall give you a sign; Behold, a virgin shall conceive, and bear a son; and ye shall call His name Emmanuel. Butter and honey shall He eat: before He knows or chooses out things that are evil, He shall exchange them for what is good; for before the child knows good or evil, He shall not consent to evil, that He may choose that which is good.” (Isa_7:10-17) Carefully, then, has the Holy Ghost pointed out, by what has been said, His birth from a virgin, and His essence, that He is God (for the name Emmanuel indicates this). And He shows that He is a man, when He says, “Butter and honey shall He eat;” and in that He terms Him a child also, [in saying,] “before He knows good and evil;” for these are all the tokens of a human infant. But that He “will not consent to evil, that He may choose that which is good,” — this is proper to God; that by the fact, that He shall eat butter and honey, we should not understand that He is a mere man only, nor, on the other hand, from the name Emmanuel, should suspect Him to be God without flesh.
Clement of Alexandria The Instructor [Paedagogus.] Book I. Chap. II.
Now, O you, my children, our Instructor is like His Father God, whose son He is, sinless, blameless, and with a soul devoid of passion; God in the form of man, stainless, the minister of His Father’s will, the Word who is God, who is in the Father, who is at the Father’s right hand, and with the form of God is God.