To add to what was written already, we believe the 73 books in our Bible were the books handed on by Christ’s apostles to the Church as part of God’s divine revelation to be read in the liturgy as sacred Scripture.
There have been times throughout Church history when the inspiration of certain books has come into question. At these times, the Magisterium of the Church (guided by the Holy Spirit) would come together and make a decision about the canon of Scripture. The Major Church Pronouncements on the Bible can be found here:
Point out to your students the example set in Acts 15 when the Apostolic Church, guided by the Holy Spirit, settled the first major controversy in the Church. The same method the Apostles used then is still used today and was used to settle the canonicity of Scripture. The Holy Spirit revealed the inspiration of the books of the Bible through the direction of the Magisterium of the Church–the bishops in union with the bishop of Rome.
You might find this online book helpful:
Where We Got the Bible: Our Debt to the Catholic Church
by The Right Rev. HENRY G. GRAHAM,
The Vatican II document, *Dei Verbum: *, explains how we received God’s divine revelation: vatican.va/archive/hist_councils/ii_vatican_council/documents/vat-ii_const_19651118_dei-verbum_en.html
The Old Testament: The plan of salvation foretold by the sacred authors, recounted and explained by them, is found as the true word of God in the books of the Old Testament: these books, therefore, written under divine inspiration, remain permanently valuable
The New Testament: 18. It is common knowledge that among all the Scriptures, even those of the New Testament, the Gospels have a special preeminence, and rightly so, for they are the principal witness for the life and teaching of the incarnate Word, our savior.
The Church has always and everywhere held and continues to hold that the four Gospels are of apostolic origin. . .
The sacred authors wrote the four Gospels, selecting some things from the many which had been handed on by word of mouth or in writing, reducing some of them to a synthesis, explaining some things in view of the situation of their churches and preserving the form of proclamation but always in such fashion that they told us the honest truth about Jesus.(4) For their intention in writing was that either from their own memory and recollections, or from the witness of those who “themselves from the beginning were eyewitnesses and ministers of the Word” we might know “the truth” concerning those matters about which we have been instructed (see Luke 1:2-4).
- Besides the four Gospels, the canon of the New Testament also contains the epistles of St. Paul and other apostolic writings, composed under the inspiration of the Holy Spirit, by which, according to the wise plan of God, those matters which concern Christ the Lord are confirmed, His true teaching is more and more fully stated, the saving power of the divine work of Christ is preached, the story is told of the beginnings of the Church and its marvelous growth, and its glorious fulfillment is foretold.
For the Lord Jesus was with His apostles as He had promised (see Matt. 28:20) and sent them the advocate Spirit who would lead them into the fullness of truth (see John 16:13)…
SACRED SCRIPTURE IN THE LIFE OF THE CHURCH
- The Church has always venerated the divine Scriptures just as she venerates the body of the Lord, since, especially in the sacred liturgy, she unceasingly receives and offers to the faithful the bread of life from the table both of God’s word and of Christ’s body. She has always maintained them, and continues to do so, together with sacred tradition, as the supreme rule of faith, since, as inspired by God and committed once and for all to writing, they impart the word of God Himself without change, and make the voice of the Holy Spirit resound in the words of the prophets and Apostles.
Also, you can read the articles about the NT and OT canon in the Catholic Encyclopedia: