Who Decided What Books Belong in the Bible?
A straightforward look at how Scripture took shape long before Nicaea.
A quick note up front: this is not a comprehensive history of canon formation. It’s a distilled overview designed to give you the essentials, supported by primary sources and reputable scholarship. If you want to go deeper, the footnotes will point you in the right direction.
Most people hear one of two stories about how the Bible came together. Either the Jews had a fixed Old Testament and the early Church simply added the New Testament, or Constantine and the Council of Nicaea invented the Bible for political reasons. Both narratives collapse under scrutiny.
The real story is slower, richer, and thoroughly documented. No council created the canon. It emerged across centuries as Jewish and Christian communities read, debated, preserved, and copied certain books until a broad consensus formed. By Nicaea, that process was almost finished.
This article explains how we know that, and you’ll find exhaustive footnotes for further research.
How the Jewish Scriptures Took Shape
The Three-Part Hebrew Canon Formed Gradually
The Hebrew Bible was not canonized in a single moment but grew in stages:
The Torah (Pentateuch) was treated as authoritative by the 5th century BCE, as shown when Ezra publicly read it to the community after the Exile.1
By the 2nd century BCE, writers such as Ben Sira referred to “the Law, the Prophets, and other writings,” indicating a two-part core (Law + Prophets) with additional revered texts not yet formally fixed.2
The Writings came last, gradually gaining canonical status over time.
Evidence of a Fixed Set by the 1st Century CE
Two major sources show a near-complete canon by the end of the 1st century:
Josephus (c. 95 CE) explicitly lists 22 sacred books that Jews believed to be divine.3
The Jewish apocalypse 4 Ezra (c. 100 CE) speaks of 24 books to be made public to all the people.4
This corresponds exactly to the later 24-book Hebrew Bible (same content as the Protestant 39-book Old Testament, but counted differently).
Jamnia Was Not a Canon Council
Older scholarship proposed a formal “Council of Jamnia” fixed the canon around 90 CE, but modern research has rejected this.
The Mishnah records rabbinic debates about books like Ecclesiastes and Song of Songs, but describes no synod defining the canon.5
Scholars such as Sid Leiman, Jack P. Lewis, and Timothy Lim demonstrate the evidence does not support a binding canonical decision.6
Instead, the Jewish canon solidified organically, especially after the destruction of the Temple in 70 CE.
Why Certain Historical Crises Pushed Israel Toward a Fixed Canon
Babylonian Exile
The loss of the Temple pushed Jews toward Scripture as the center of communal life. Ezra and Nehemiah’s reforms centered on the public reading of Torah, showing its authoritative role.7
Hellenistic Pressure and the Maccabean Crisis
During Antiochus IV’s persecutions (2nd century BCE), observance of Torah was outlawed, copies were burned, and Jewish identity was threatened.
2 Maccabees records that Judas Maccabeus collected the sacred books after the revolt.8
This suggests a recognized set of sacred writings already in use.
After 70 CE
Following the destruction of the Temple:
Judaism reorganized around Torah and synagogue.
Rabbis debated borderline books like Esther, Ecclesiastes, and Song of Songs.9
Certain “outside books” were discouraged; Rabbi Akiva explicitly warned against reading noncanonical works.10
By the 2nd century CE, the 24-book Hebrew canon was widely accepted in rabbinic Judaism.
Why the Jewish Canon Was 24 Books—Not 39
One point often misunderstood in modern discussions is the number of books in the Jewish Scriptures. Today’s Protestant Old Testament contains 39 books, but ancient Judaism recognized 24. This is not because Protestants added books or Jews removed them. The difference is simply a matter of book division, not content.
Ancient Jews combined several books that later Christian communities separated into individual volumes. For example, the twelve Minor Prophets, Hosea through Malachi, were originally treated as one book, called “The Twelve.” Likewise, Samuel, Kings, and Chronicles each counted as one book, not two. Ezra and Nehemiah formed one unified work, and in some traditions, Ruth was attached to Judges and Lamentations to Jeremiah to reduce the total count.
This explains the numerical change:
Jewish Canon: 24 books
Josephus’ Count: 22 books (a different grouping of the same material)
Protestant OT: 39 books (same content, more divisions)
Nothing was added or removed, it was only rearranged and split.
This 24-book canon is the form consistently reflected in ancient Jewish sources:
Josephus (c. 95 CE) speaks of 22 books that correspond to the same content as the later 24-book canon.
4 Ezra 14 (c. 100 CE) explicitly lists 24 public books given for the people.
Rabbinic sources (Bava Batra 14b–15a) also treat the Scriptures as a 24-book collection.
So although modern English Bibles list 39 books, that number represents a later Christian method of formatting, not a different canon. When we talk about the Jewish canon at the time of Jesus or during the formation of the early Church, we are talking about a 24-book Tanakh, recognized in broad outline by the end of the 1st century and preserved in Jewish tradition ever since.
The Septuagint: The Bible of the Early Church
What the Septuagint Contained
Beginning in the 3rd–2nd centuries BCE, the Hebrew Scriptures were translated into Greek in Alexandria. The Septuagint (LXX) included:
All books of the Hebrew Bible
Additional Jewish writings such as Tobit, Judith, Wisdom of Solomon, Sirach, Baruch, and 1–2 Maccabees11
These books were not segregated.. they were mixed into the scriptural collection.
Why Christians Used the Septuagint
Christianity spread first in the Greek-speaking world, so the LXX naturally became the Church’s Old Testament.
Evidence includes:
Most New Testament quotations of the OT match the Septuagint wording.12
Matthew’s use of Isaiah 7:14 (“virgin” = parthenos) follows the LXX, not the Hebrew.13
Irenaeus argued Jews later altered the Hebrew text to undermine Christian readings.14
Why Jews Abandoned It
By the 2nd century CE:
Rabbinic Judaism increasingly rejected the LXX because Christians used it to argue Jesus was Messiah.
New Greek translations (Aquila, Theodotion, Symmachus) were created that aligned more closely with the Hebrew.15
How Christians Recognized the New Testament Books
Apostolic Writings Gain Immediate Authority
Paul’s letters were circulated and treated as authoritative by the late 1st century CE.
2 Peter 3:16 refers to Paul’s letters as “Scriptures.”16
The four canonical Gospels were written between 65–100 CE.
Early 2nd-Century Witnesses
1 Clement (c. 95 CE) quotes from NT writings with scriptural authority.17
Ignatius and Polycarp use Gospel and Pauline material as binding.18
Justin Martyr reports that the “memoirs of the apostles” were read every Sunday alongside the prophets.19
Late 2nd-Century Evidence
Irenaeus insists on exactly four Gospels, rejecting others.20
The Muratorian Fragment (c. 170–200 CE) lists nearly all 27 NT books and excludes others.21
Origen’s Third-Century Snapshot
Origen (185–254 CE):
Used all 27 books of the NT.
Noted that some (James, 2 Peter, 2–3 John, Jude) were disputed in some regions.22
By the early 300s, 22 of the 27 were widely accepted.
The Criteria the Early Church Used
Early Christian writers describe several criteria the Church implicitly used:
Apostolicity
Books had to come from the apostles or their close companions.
Works like the Gospel of Thomas and Gospel of Peter were rejected because they were late and pseudonymous.23
Orthodoxy
Books had to agree with the apostolic “rule of faith.” (Teachings of the apostles that were used as a guide for what real Christianity is supposed to look like, and what it’s not.)
Serapion of Antioch rejected the Gospel of Peter when he found it taught docetism.24
Catholicity (Universal Use)
Books needed widespread usage across apostolic churches.
Liturgy (public reading) became a major indicator.
Antiquity
Post-apostolic writings (for example, Shepherd of Hermas, Barnabas) were excluded even when widely loved.25
Spiritual Recognition
Books recognized in worship as inspired were retained; others fell away.
Why Some Books Were Not Canonized
Loved but Excluded
Shepherd of Hermas was quoted positively by Irenaeus and included in Codex Sinaiticus, but rejected as non-apostolic.26
Epistle of Barnabas was used by Alexandrian Fathers but listed as “spurious” by Eusebius.27
Didache was valued but excluded for the same reason.28
Quoted but Not Canonical
1 Enoch is quoted in Jude 14–15.29
Used by early Fathers (Barnabas, Justin, Irenaeus, Clement, Tertullian),
but excluded because it wasn’t part of the Hebrew canon and contained speculative cosmology.30
Heretical Writings
Eusebius lists works like Gospel of Thomas, Gospel of Peter, Acts of John, etc., as “absurd and impious” and totally rejected.31
Disputed but Ultimately Included
James, Jude, 2 Peter, 2–3 John, and Revelation were accepted after regional debates settled in the 4th century.32
What the Canon Looked Like at Nicaea
Old Testament
Jews recognized the 24-book Hebrew canon.
Christians primarily used the Septuagint (LXX), including the deuterocanonical books.33
No universal Christian decree yet distinguished canonical vs. non-canonical LXX books.
New Testament
As of Eusebius (c. 320s CE):
Accepted:
Gospels, Acts, Pauline epistles (including Hebrews), 1 Peter, 1 John, and (in some lists) Revelation.34
Disputed but used by many:
James, Jude, 2 Peter, 2–3 John.35
Rejected (spurious):
Hermas, Barnabas, Apocalypse of Peter, Didache, Acts of Paul.36
Condemned as heretical:
Gospels of Peter, Thomas, Matthias, and apocryphal Acts.37
After Nicaea:
Athanasius’s Festal Letter 39 (367 CE) lists the exact 27 NT books used today.38
Councils of Rome (382), Hippo (393), and Carthage (397) confirm the same list.39
Nicaea issued no canon list.
The “altar test” story: placing books on an altar to see which stayed.. is only found in the Synodicon Vetus (9th century) and is universally regarded as legend.40
Footnotes
Nehemiah 8; see also Ezra–Nehemiah for Torah-centered reforms.
Sirach Prologue; dates c. 180–130 BCE.
Josephus, Against Apion 1.37–43.
4 Ezra (2 Esdras) 14:44–48.
Mishnah, Yadayim 3:5.
Sid Z. Leiman, The Canonization of Hebrew Scripture; Jack P. Lewis, “What Do We Mean by Jabneh?”; Timothy Lim, AJR (2015).
Ezra 7–10; Nehemiah 8.
2 Maccabees 2:13–15.
Mishnah, Yadayim 3:5.
Talmud, Sanhedrin 100b; cf. Akiva on “outside books.”
LXX manuscripts: Codex Vaticanus, Sinaiticus, Alexandrinus.
NT quotations analyzed in Jobes & Silva, Invitation to the Septuagint.
Matthew 1:23 quoting Isaiah 7:14 LXX.
Irenaeus, Against Heresies 3.21.1.
Origen, Hexapla references; see Eusebius, HE 6.16–17.
2 Peter 3:15–16.
1 Clement 47; 49.
Ignatius (Ephesians, Romans), Polycarp (Philippians).
Justin Martyr, First Apology 67.
Irenaeus, Against Heresies 3.11.8.
Muratorian Canon (Fragment).
Eusebius, Ecclesiastical History 6.25.
Eusebius, HE 3.25.
Eusebius, HE 6.12.3–6.
Tertullian, On Modesty 20; Origen, HE 6.25.
Irenaeus, AH 4.20.2; Codex Sinaiticus includes Hermas.
Eusebius, HE 3.25.4.
Eusebius, HE 3.25.4.
Jude 14–15 quoting 1 Enoch 1:9.
Tertullian, On the Apparel of Women 1.3; Origen dismissed books of Enoch.
Eusebius, HE 3.25.6.
Eusebius, HE 3.25; Athanasius confirms final acceptance.
LXX usage: Justin, Irenaeus, Origen; evident in early manuscripts.
Eusebius, HE 3.25.1–3.
Eusebius, HE 3.25.3.
Eusebius, HE 3.25.4.
Eusebius, HE 3.25.6.
Athanasius, Festal Letter 39 (367 CE).
Decretum Gelasianum (Council of Rome 382); Councils of Hippo (393) & Carthage (397) canons.
Synodicon Vetus §§ 30–31; see also modern critical discussions in Metzger, Canon of the NT.
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