Why Catholics Have 73 Books In The Bible
In history, some people have been tempted not just to leave unread but even to reject parts of the Bible that did not suit them. The Catholic Church has declared that there are 73 books in the Bible - 46 of the Old Testament and 27 of the New. The Church took several centuries to define the dogmas about Jesus at the various ecumenical councils. Similarly she took centuries to define the Canon of Scripture, i.e. those books which are inspired by the Holy Spirit. There were various opinions about whether certain books belonged in the Bible. In the 39th festal letter of St. Athanasius in 367 AD he lists the twenty-seven books of the New Testament. This list is the earliest clear reference we have to the present canon of the New Testament.
With regard to the canon of both the Old Testament and the New Testament, the important rulings were those of the Synod at Hippo (393 AD) and the Council of Carthage (397 AD), both of which listed the 73 books which the Catholic Church accepts as canonical. In 419 AD, the Council of Carthage reaffirmed this list. This was subject to the approval of the Pope. In 404 AD, Pope Innocent 1 wrote a letter to the Bishop of Toulouse reaffirming this canon of 73 books.
By 405 AD, St. Jerome had translated the Bible into Latin and included all 73 books. This was the Bible used throughout the western world up till the time of the Reformation.
In the 1500s the reformers removed 7 Old Testament books which had been in universal use up till then. The difference between the Catholic and Protestant canons of Scripture consists in the acceptance or rejection of these 7 books. They were not part of the Hebrew Bible but, written in Greek, were part of the Septuagint Bible, the Greek version of the Old Testament used by Jews and Christians outside Palestine. These 7 books are termed 'Deuterocanonical'. The Catholic Church teaches that they are fully canonical and inspired by the Holy Spirit. They were part of the Old Testament used by Christians from the beginning of Christianity.
In the 1500s Martin Luther, following the Hebrew Bible's list of books, regarded these 7 books as apocryphal, that is, not canonical and not inspired by the Holy Spirit. Despite this, Lutheran editions of the Bible often include these books, whereas other Protestant editions of the Bible did not. Luther, despite misgivings, accepted all 27 books of the New Testament as canonical.
But the Bible was given to the People of God: Israel in the Old Testament times and the Catholic Church from the time of Jesus Christ. It would seem absurd to have inspired books to teach us if we did not know what those books were. As the Bible says, it is the Church "which is the pillar and foundation of truth" (1 Timothy 3:15) and it is the Church which has been given from Jesus to speak in His Name, and to teach us what we must believe. As part of this authority which the Catholic Church alone has, she is able to teach with certainty what books are inspired.
The Catholic Church teaches that-----------God Himself is the author of Sacred Scripture. For this reason it is said to be inspired and to teach without error those truths which are necessary for our salvation. The Holy Spirit inspired the human authors who wrote what He wanted to teach us. The Christian faith, however, is not a "religion of the Book". but the Word of God - "not a written and mute word, but incarnate and living". (Saint Bernard of Clairvaux). (Compendium of the Catechism of the Catholic Church 18)
Sacred Scripture gives support and vigor to the life of the Church. For the children of the Church, it is a confirmation of the faith, food for the soul and the fount of the spiritual life. Sacred Scripture is the soul of theology and of pastoral preaching. The Psalmist says that it is a "lamp to my feet and a light to my path" (Psalm 119:105). The Church, therefore, exhorts all to read Sacred Scripture frequently because "ignorance of the scriptures is ignorance of Christ" (Saint Jerome) (Compendium of the Catechism of the Catholic Church 24).
Source: Catholic Contact