Each Christian has the need to read Holy Scripture, yet each Christian does not also have the authority or ability to teach and interpret the words of Scripture. This privileged authority is reserved for the Church via its holy clergy and theologians, men who are instructed in and knowledgeable of the true faith. When we consider how our Saviour gave the grace of teaching to His Holy Apostles (Mat. 28:20) and not to the masses it is easy for us to see that the prerogative to teach is held only by the bishops, priests and theologians of our Church. It was the Apostles who were sent by Christ to teach and to celebrate the Holy Mysteries (Sacraments). Our Apostle Paul says: “How shall they preach, except they be sent?” (Rom. 10:15). Accordingly, the bishops are the lawful successors to the Apostles and those sent for the preaching (êÞñõãìá) to the people. Paul entrusts the heavy burden of the instruction of the people to Timothy and not to the faithful. He speaks of this elsewhere: “Are all apostles? Are all prophets? Are all teachers?” (1 Cor. 12:29) Again he says to Timothy that the clergy must be “apt to teach” others (1 Tim. 3:2). He does not, however, say the same thing for the faithful. He makes a distinction between shepherd and sheep, between teacher and those taught.
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No, [the Holy Scripture] is not sufficient to guide man to salvation, [2] inasmuch as, firstly, it wasn’t given to man from the beginning and, secondly, when it was given it wasn’t the only authentic text, with regard to the salvation of human souls, because before it there was the Holy Tradition. Many years before Moses began writing the first books of the Old Testament, there was sacred piety in the community of the people of Israel. Similarly, the books of the New Testament began to be written ten years after the formal foundation of the Church, which took place on the day of Pentecost. The Church chose and sealed as inspired by God the books of the two Testaments over one hundred years later.[3] These then comprised the declared Canon of the books of Holy Scripture. Thereafter the Church maintained this Canon of Truth, inasmuch as it is the very “pillar and ground of truth” (1 Tim. 3:15). The Holy Spirit operates within all of this for the preservation of the truth about salvation. Where the Church is, says Saint Jerome, there also is the Spirit of God and where the Spirit of God is, there also is the Church and all grace - since the Spirit is truth.
Holy Tradition is the teaching of the Church, God-given with a living voice, from which a portion was later written down. As with Holy Scripture, so, too, Holy Tradition contains Holy Revelation, and is, therefore, fundamental for our salvation. Holy Tradition is the life of the Church in the Holy Spirit and, consonant with the enduring life of the Church, is thus a wellspring of Holy Revelation, such that, consequently, it possesses the same authority as Holy Scripture.
From the time of Adam until that of Abraham, according to the old chronologies, 3,678 years passed, and if we add 430 years when the Israelites remained in Egypt, we have 4,108 years. Throughout this period of time Holy Scripture neither existed nor was the Sabbath considered as a feast among the people. During this period of many thousands of years the faithful and chosen people were guided to the path of salvation only by Holy Tradition, namely, from the teachings about God which they received from a living voice. Only for the duration of 1400 years - from the time of Moses until the advent of Christ - were they guided by the Holy Scriptures of the Old Testament.
Just as before the books of the Old Testament were written the people were guided in the knowledge of God and on the path of salvation only by Holy Tradition (Tradition with a living voice, orally), so too were they precisely before the writing of the books of the New Testament. The Holy Tradition was the guide by which the first Christians were directed to the path of salvation. The first to impart the teachings of the New Testament with a living voice to the ears of the people was our Saviour Jesus Christ Himself, who for three and a half years continually taught the people, distributing His Gospel without, however, writing anything. Inasmuch as He was carrying out obedience to His Father, He didn’t send His Apostles to write but to preach the Gospel to the whole world, saying to them: “Go ye therefore, and teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Spirit: Teaching them to observe all things whatsoever I have commanded you: and lo, I am with you always, even unto the end of the world. Amen” (Mat. 28:19-20). From the day of its establishment (33 AD) until the year 44 AD, when the the Holy Apostle Matthew wrote the first Gospel [1], the Church was governed without the Scriptures of the New Testament, but only with the Holy Tradition of which only a part was later recorded. Although there were many other writers for whom it was claimed that they were inspired and faithful scribes of the Apostles, the Church is She who did or did not recognise them, for She is unerring. The Church lived the truth of the Gospel even before anything was committed to writing, having lived with the Holy Tradition from the outset.
So then, this is the Holy Tradition: The source and the root of the two Testaments - the Old and the New - and thus the reason why we call it a source of Holy Revelation, since it carries the same weight as Holy Scripture.
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... the law of God is not only contained in Holy Scripture. Listen to what the divine Evangelist John says: “And there are also many other things which Jesus did, the which, if they should be written every one, I suppose that even the world itself could not contain the books that should be written. Amen” (Jn. 21:25). Again the same Evangelist declares in one of his epistles: “Having many things to write unto you, I would not write with paper and ink: but I trust to come unto you, and speak face to face, that our joy may be full” (2 Jn. 1:12). So, you see that the holy evangelist, when he had the ability, taught his disciples more with the living voice of Tradition than by sending them epistles. While your friends keep at all costs only so much as is written, they don’t take into account that both the Saviour and the majority of His Apostles did not leave anything written, but rather taught orally, with the living voice of Tradition.