Tambok,
I don’t know if you realize it, but you actually answered your own question. You said in part: “My question is why we (Catholics) have this books and what is the authenticity of including this books in the bible?”
Instead of asking ONLY about the deuterocanonical books, ask the next logical question: what is the authenticating factor in including ANY books in the bible?
The “process” for including/excluding books such as The Gospel of St. Matthew, St. Mark, St. Luke, and St. John, is EXACTLY the same that was used to compile the remainder of the Bible.
We did not need the Church to WRITE the inspired scriptures - but we certainly needed it to review all of the various, purported “divinely inspired” manuscripts floating around during Jerome’s time so that the Church could properly instruct Jerome to compile THE bible (The Latin Vulgate) as the bible to be used by the Church and all her faithful. The Council on Trent makes this very clear:
*SESSION THE FOURTH
Celebrated on the eighth day of the month of April, in the year MDXLVI.
DECREE CONCERNING THE CANONICAL SCRIPTURES
The sacred and holy, ecumenical, and general Synod of Trent,–lawfully assembled in the Holy Ghost, the Same three legates of the Apostolic Sec presiding therein,–keeping this always in view, that, errors being removed, the purity itself of the Gospel be preserved in the Church; which (Gospel), before promised through the prophets in the holy Scriptures, our Lord Jesus Christ, the Son of God, first promulgated with His own mouth, and then commanded to be preached by His Apostles to every creature, as the fountain of all, both saving truth, and moral discipline; and seeing clearly that this truth and discipline are contained in the written books, and the unwritten traditions which, received by the Apostles from the mouth of Christ himself, or from the Apostles themselves, the Holy Ghost dictating, have come down even unto us, transmitted as it were from hand to hand; (the Synod) following the examples of the orthodox Fathers, receives and venerates with an equal affection of piety, and reverence, all the books both of the Old and of the New Testament–seeing that one God is the author of both --as also the said traditions, as well those appertaining to faith as to morals, as having been dictated, either by Christ’s own word of mouth, or by the Holy Ghost, and preserved in the Catholic Church by a continuous succession. And it has thought it meet that a list of the sacred books be inserted in this decree, lest a doubt may arise in any one’s mind, which are the books that are received by this Synod. They are as set down here below: of the Old Testament: the five books of Moses, to wit, Genesis, Exodus, Leviticus, Numbers, Deuteronomy; Josue, Judges, Ruth, four books of Kings, two of Paralipomenon, the first book of Esdras, and the second which is entitled Nehemias; Tobias, Judith, Esther, Job, the Davidical Psalter, consisting of a hundred and fifty psalms; the Proverbs, Ecclesiastes, the Canticle of Canticles, Wisdom, Ecclesiasticus, Isaias, Jeremias, with Baruch; Ezechiel, Daniel; the twelve minor prophets, to wit, Osee, Joel, Amos, Abdias, Jonas, Micheas, Nahum, Habacuc, Sophonias, Aggaeus, Zacharias, Malachias; two books of the Machabees, the first and the second. Of the New Testament: the four Gospels, according to Matthew, Mark, Luke, and John; the Acts of the Apostles written by Luke the Evangelist; fourteen epistles of Paul the apostle, (one) to the Romans, two to the Corinthians, (one) to the Galatians, to the Ephesians, to the Philippians, to the Colossians, two to the Thessalonians, two to Timothy, (one) to Titus, to Philemon, to the Hebrews; two of Peter the apostle, three of John the apostle, one of the apostle James, one of Jude the apostle, and the Apocalypse of John the apostle. But if any one receive not, as sacred and canonical, the said books entire with all their parts, as they have been used to be read in the Catholic Church, and as they are contained in the old Latin vulgate edition; and knowingly and deliberately contemn the traditions aforesaid; let him be anathema. Let all, therefore, understand, in what order, and in what manner, the said Synod, after having laid the foundation of the Confession of faith, will proceed, and what testimonies and authorities it will mainly use in confirming dogmas, and in restoring morals in the Church.*
