Pick up a Bible and flip through it. Two-thirds is Old Testament; one-third is New. They were written across roughly 1,500 years, in three languages (Hebrew, Aramaic, and Greek), by dozens of authors on three continents. Yet Christians across all traditions read them as one book — the story of God and humanity — with the Old Testament as the foundation and the New Testament as the fulfillment.
Understanding the difference between the two doesn't require a theology degree. It requires knowing what each contains, why both matter, and how they connect.
Key Takeaways
- The Old Testament: 39 books (Protestant), 46 (Catholic), 49+ (Orthodox) — written in Hebrew and Aramaic.
- The New Testament: 27 books in all Christian traditions — written in Greek.
- The OT tells God's covenant with Israel; the NT reveals Jesus as the fulfillment of that covenant.
- Christians believe the OT foreshadows and the NT fulfills — typology (reading OT events as previews of Christ) is central to this.
- Best NT starting point: Mark or John. Best OT starting point: Genesis 1–11 then Psalms.
What Is the Old Testament?
The Old Testament (OT) is the first and larger part of the Christian Bible. It is nearly identical to the Jewish Bible (the Tanakh), with some differences in arrangement and, for Catholics and Orthodox, additional books. The OT contains:
- The Torah / Pentateuch (Genesis–Deuteronomy): The first five books, attributed to Moses. Contains the creation story, the patriarchs (Abraham, Isaac, Jacob, Joseph), the Exodus from Egypt, and the Law given at Sinai.
- Historical Books (Joshua–Esther): The story of Israel entering Canaan, the judges, the monarchy (Saul, David, Solomon), the split kingdom, the Babylonian exile, and the return.
- Wisdom Literature (Job, Psalms, Proverbs, Ecclesiastes, Song of Solomon): Poetry, prayers, philosophy, and love poetry.
- The Prophets (Isaiah–Malachi): Writings from prophets who called Israel back to faithfulness and announced coming judgment and restoration.
Citation Capsule — The Old Testament The Old Testament (39 books, Protestant) was written primarily in Hebrew and Aramaic over roughly 1,000 years (c. 1000–400 BCE). It tells the story of God's covenant with Israel — from creation through the patriarchs, Exodus, monarchy, exile, and the prophets' promise of restoration. It is the same corpus as the Jewish Tanakh, organized differently by Christian traditions.
What Is the New Testament?
The New Testament (NT) is the second part of the Christian Bible and identical in all Christian traditions: 27 books, written in Greek over roughly 50 years (c. 50–100 CE). It contains:
- The Four Gospels (Matthew, Mark, Luke, John): Four accounts of the life, death, and resurrection of Jesus. Each has a distinct perspective and audience.
- Acts of the Apostles: The story of the early Church from Pentecost through Paul's journeys to Rome.
- Paul's Letters (Romans–Philemon): 13 letters from Paul to early Christian communities, explaining the meaning of Christ's death and resurrection for daily life and theology.
- General Letters (Hebrews–Jude): Letters from James, Peter, John, and Jude to broader audiences.
- Revelation: A prophetic vision of the end of history, written by John.
Citation Capsule — The New Testament The New Testament contains 27 books written in Greek over roughly 50 years (c. 50–100 CE). It begins with four accounts of Jesus (the Gospels), continues with the history of the early Church (Acts), and includes 21 letters (epistles) and the prophetic Revelation. All 27 books are identical across Catholic, Protestant, and Orthodox canons.
Key Differences at a Glance
| Feature | Old Testament | New Testament |
|---|---|---|
| Books (Protestant) | 39 | 27 |
| Books (Catholic) | 46 | 27 |
| Languages | Hebrew, Aramaic | Greek |
| Written | c. 1400–400 BCE | c. 50–100 CE |
| Main focus | God's covenant with Israel | Jesus: his life, death, resurrection, and the early Church |
| Central figure | Yahweh / God | Jesus of Nazareth |
| Law | Mosaic law given at Sinai | New covenant through Christ |
| Key genres | Narrative, law, poetry, prophecy | Gospel, letter, prophecy |
How Do the Two Testaments Connect?
The Christian understanding is that the OT prepares for and foreshadows what the NT fulfills. This is called typology — the OT contains "types" (previews or patterns) that are completed in Christ.
Examples:
- Adam (Genesis 2–3) is called "a pattern of the one to come" — Paul explicitly calls Christ "the last Adam" in 1 Corinthians 15:45 (NIV)
- The Passover lamb (Exodus 12) prefigures Christ as "the Lamb of God" (John 1:29 NIV)
- The sacrificial system (Leviticus) is explained in Hebrews as a "shadow" of Christ's once-for-all sacrifice (Hebrews 10:1 NIV)
- The servant songs of Isaiah (Isaiah 42, 49, 50, 52–53) are quoted in all four Gospels as fulfilled by Jesus
Citation Capsule — The OT-NT Connection Christian theology reads the Old Testament as pointing forward to Christ through typology: Adam/Christ (1 Corinthians 15:45 NIV), Passover lamb/Lamb of God (John 1:29 NIV), temple sacrifice/Christ's once-for-all offering (Hebrews 10:1 NIV). Jesus affirmed this in Luke 24:27 (NIV), explaining "what was said in all the Scriptures concerning himself."
Where Should You Start Reading?
For most beginners, the best approach is to start with the NT (the story of Jesus), then work back into the OT with that context. The OT was written first chronologically, but the NT gives you the interpretive lens that Christians use to read it.
New Testament starting points:
- Mark (16 chapters, ~1.5 hours) — the shortest, fastest Gospel. Pure action.
- John (21 chapters) — the most reflective Gospel, written for outsiders who've never heard of Jesus.
- Acts — the sequel to Luke; tells the story of the early Church.
Old Testament starting points:
- Genesis 1–11 — creation, the Fall, Noah, the Tower of Babel
- Genesis 12–50 — Abraham, Isaac, Jacob, Joseph
- Psalms — the prayer and songbook; 150 poems covering every human emotion
- Isaiah 40–55 — the most-quoted OT section in the NT; majestic prophecy
Frequently Asked Questions
What is the main difference between the Old and New Testament?
The Old Testament tells the story of God's covenant with Israel — from creation through the Exodus, monarchy, exile, and prophets. The New Testament presents Jesus as the fulfillment of that covenant, recording his life, death, and resurrection, and the growth of the early Church. The OT has 39 books (Protestant); the NT has 27 books shared by all traditions.
Should I read the Old Testament or New Testament first?
Most beginners do better starting with the New Testament — specifically the Gospel of Mark. The NT gives you the interpretive lens (Jesus as fulfillment of OT prophecy) before you wade into OT law codes and genealogies. Once you've read the NT, the OT makes considerably more sense.
Does the New Testament replace the Old Testament?
No — Christian theology says the NT fulfills and completes the OT, not replaces it. Jesus said in Matthew 5:17 (NIV): "Do not think that I have come to abolish the Law or the Prophets; I have not come to abolish them but to fulfill them." All three major traditions (Catholic, Protestant, Orthodox) treat both Testaments as Scripture.
Are the Old Testament and the Hebrew Bible the same thing?
Nearly identical. The Protestant OT and the Jewish Tanakh contain the same 39 books (though organized differently). Catholic and Orthodox OTs include additional books (the deuterocanonical/apocryphal books) that the Jewish canon does not contain. The content of the shared 39 books is the same.
How many books are in the Old and New Testament?
Protestant: 39 OT + 27 NT = 66 total. Catholic: 46 OT + 27 NT = 73 total. Orthodox: 49+ OT + 27 NT = 76+ total. All traditions share the identical 27-book New Testament.