The Bible contains many different types of writing—history, poetry, prophecy, law, wisdom literature, letters, and visions. These writings were composed in different times and places, by different human authors, and in several languages.
Yet despite this diversity, the Church teaches that the Bible is one unified book. All of Scripture speaks with one voice, because all of it is inspired by the Holy Spirit, and all of it is fulfilled in Christ. It tells a single, unfolding story: the story of God's covenant with His people, which finds its fullness in the life, death, and resurrection of Jesus Christ.
The Bible is traditionally divided into two main parts: the Old Testament and the New Testament. The Old Testament prepares for the coming of Christ, while the New Testament proclaims His fulfillment. The two Testaments are not separate revelations, but parts of one divine plan.
“The New Testament lies hidden in the Old, and the Old is unveiled in the New.”
—St. Augustine
The Old Testament
The Old Testament contains the sacred writings of ancient Israel. It includes books of history, law, prophecy, poetry, and wisdom. These texts bear witness to God's covenant with His people and prepare the way for the coming of the Messiah.
The number of books in the Old Testament differs slightly between Christian traditions, due to variations in which texts were received and preserved from the earliest times:
- In the Western Church, the Old Testament typically includes 46 books. These include the so-called “Deuterocanonical” books such as Tobit, Judith, Wisdom, Sirach (Ecclesiasticus), Baruch, and 1 & 2 Maccabees.
- In the Eastern Church, the canon is similar but may include up to 49 books, depending on the tradition.
- Some Eastern Christian Bibles—including those used by Eastern Orthodox, Eastern Catholic, and Oriental Orthodox Churches—also include books such as 3 Maccabees, 1 Esdras, and Psalm 151. These are sometimes referred to as Anaginoskomena (books that are read), especially in the Eastern tradition.
These differences reflect the diverse ways the early Church received and preserved Scripture—especially as the Septuagint was used more broadly in the East, and Latin translations took prominence in the West.
Despite these differences in detail, the essential core of the Old Testament is shared, and the message remains unified: God calling, forming, and preparing His people for salvation.
The New Testament
The New Testament is identical in all historic Christian traditions and includes 27 books. These are:
- The four Gospels (Matthew, Mark, Luke, and John), which proclaim the life, teachings, death, and resurrection of Jesus Christ.
- The Acts of the Apostles, which describes the early Church’s mission and expansion.
- A collection of epistles (letters) written by apostles such as Paul, Peter, James, and John to early Christian communities.
- The Book of Revelation, a vision of divine judgment and hope for the future.
These writings were all composed in the first century AD and were recognized by the Church as authoritative witnesses to Christ and the apostolic faith.
A Harmony Across Traditions
While the Old Testament canon may vary slightly between East and West, the message and authority of Scripture are upheld in both traditions. The Church—guided by the Holy Spirit—has preserved and handed down the Scriptures as a sacred trust.
The structure of the Bible reflects the unity of God’s plan: the Old Testament prepares the way; the New Testament reveals its fulfillment in Christ.
Next: Part 3 – Inspiration and How to Read the Bible →