No, it was not...the canon was already established by the 2nd century, long before Constantine came on the scene...you don't know your history...
ustin Martyr (died c. 165 C.E.) in his “Dialogue With Trypho, a Jew” (XLIX), used the expression “it is written” when quoting from Matthew, in the same way the Gospels themselves do when referring to the Hebrew Scriptures. The same is also true in an earlier anonymous work, “The Epistle of Barnabas” (IV). Justin Martyr in “The First Apology” (LXVI, LXVII) calls the “memoirs of the apostles” “Gospels.”—The Ante-Nicene Fathers, Vol. I, pp. 220, 139, 185, 186.
Theophilus of Antioch (2nd century C.E.) declared: “Concerning the righteousness which the law enjoined, confirmatory utterances are found both with the prophets and in the Gospels, because they all spoke inspired by one Spirit of God.” Theophilus then uses such expressions as ‘says the Gospel’ (quoting Mt 5:28, 32, 44, 46; 6:3) and “the divine word gives us instructions” (quoting 1Ti 2:2 and Ro 13:7, 8).—The Ante-Nicene Fathers, 1962, Vol. II, pp. 114, 115, “Theophilus to Autolycus” (XII, XIII).
Canon — Watchtower ONLINE LIBRARY
Funny it is that Elvira is using the Watchtower Online Library as support for claims about the canonicity of various books found in today's New Testament.
In the "Dialogue with Trypho", Justin Martyr never names the source for his words, though some of what Justin supposedly says to Trypho may be found in Matthew 21:12-13, there are more words than we can read in Matthew.
For He appeared distasteful to you when He cried among you, 'It is written, My house is the house of prayer; but ye have made it a den of thieves!' He overthrew also the tables of the money-changers in the temple, and exclaimed, 'Woe unto you, Scribes and Pharisees, hypocrites! because ye pay tithe of mint and rue, but do not observe the love of God and justice. Ye whited sepulchres! appearing beautiful outward, but are within full of dead men's bones.' And to the Scribes, 'Woe unto you, Scribes! for ye have the keys, and ye do not enter in yourselves, and them that are entering in ye hinder; ye blind guides!'
A passage that I found rather interesting, since Justin Martyr is often seen as an early Church father with great influence on the beliefs of the 2nd century Church is the following.
CHAPTER LVI -- GOD WHO APPEARED TO MOSES IS DISTINGUISHED FROM GOD THE FATHER.
"Moses, then, the blessed and faithful servant of God, declares that He who appeared to Abraham under the oak in Mamre is God, sent with the two angels in His company to judge Sodom by Another who remains ever in the supercelestial places, invisible to all men, holding personal intercourse with none, whom we believe to be Maker and Father of all things; for he speaks thus: 'God appeared to him under the oak in Mamre, as he sat at his tent-door at noontide. And lifting up his eyes, he saw, and behold, three men stood before him; and when he saw them, he ran to meet them from the door of his tent; and he bowed himself toward the ground, and said;' 'Abraham got up early in the morning to the place where he stood before the Lord: and he looked toward Sodom and Gomorrah, and toward the adjacent country, and beheld, and, lo, a flame went up from the earth, like the smoke of a furnace.'" And when I had made an end of quoting these words, I asked them if they had understood them.
And they said they had understood them, but that the passages adduced brought forward no proof that there is any other God or Lord, or that the Holy Spirit says so, besides the Maker of all things.
Then I replied, "I shall attempt to persuade you, since you have understood the Scriptures,[of the truth] of what I say, that there is, and that there is said to be, another God and Lord subject to the Maker of all things; who is also called an Angel, because He announces to men whatsoever the Maker of all things--above whom there is no other God--wishes to announce to them." And quoting once more the previous passage, I asked Trypho, "Do you think that God appeared to Abraham under the oak in Mature, as the Scripture asserts?"
He said, "Assuredly."
"Was He one of those three," I said, "whom Abraham saw, and whom the Holy Spirit of prophecy describes as men?"
He said, "No; but God appeared to him, before the vision of the three. Then those three whom the Scripture calls men, were angels; two of them sent to destroy Sodom, and one to announce the joyful tidings to Sarah, that she would bear a son; for which cause he was sent, and having accomplished his errand, went away."
Justin saying to Trypho that there are two Gods, one superior to the other, is a basic premise of the Marcionites.