The two sources of Divine Truth are: (1) Holy Scripture and (2) Sacred Tradition (also known as Apostolic Tradition or simply Tradition).
1. One source of Divine Truth is Holy Scripture.
Holy Scripture (or the Bible) is the collection of books accepted as definitive by the Catholic Church. Sacred Scripture is the authentic, inspired record of the revelations made to mankind by God about Himself and about His Will for men. It is divided into the Old and New Testaments in order to distinguish between the earlier Covenant between God and the Jewish nation, given to Moses on Mount Sinai, and the later definitive Covenant between God and the followers of Jesus Christ throughout the world.
In the New Testament, the Old Testament is generally spoken of as “the Scriptures” or the “sacred writings” (cf. Matthew 21:42). Gradually the word “Scripture” has become a synonym for the Bible as a whole. “Testament” has the meaning of “covenant,” with reference to the two covenants which God established with His People in human history.
The Catholic Church has, more than once, taught which books are to be regarded as inspired, and which, therefore, belong to the Bible. The complete list of sacred books in the Bible is called the canon of Scripture. It is made up of forty-six books for the Old Testament and twenty-seven books for the New Testament. The four Gospels in the New Testament (Matthew, Mark, Luke, and John) are the heart of all the Scriptures because they encompass the life and teachings of our Savior, Jesus Christ.
At the Ecumenical Council of Trent, in 1546, the biblical canon was solemnly defined, and the Latin Vulgate version of the Bible, written by St. Jerome, was declared to be authentic. In 1943, Pope Pius XII reconfirmed the biblical canon and the authenticity of the Vulgate. But he made some important declarations which encouraged other translations of the Bible based on the Hebrew and Greek manuscripts.
2. The second source of Divine Truth is Sacred Tradition (also known as Apostolic Tradition or simply Tradition).
The term “tradition” literally means, a “handing on,” referring to the passing down of God’s revealed word. It has two distinct meanings.
First, Tradition means all of divine revelation, from the dawn of human history to the end of the apostolic age, as it has been passed on from one generation of believers to the next, and as it is preserved under divine guidance by the Church established by Christ.
Tradition also means, within all transmitted revelation, that part of God’s revealed word which is not contained in Sacred Scripture. The Second Vatican Council tells us how Sacred Tradition was handed on: “It was done by the apostles who handed on, by the spoken word of their preaching, by the example they gave, by the institutions they established, what they themselves had received–whether from the lips of Christ, from his way of life and his works, or whether they had learned it at the prompting of the Holy Spirit” (Dei Verbum, 7).