Who wrote the Bible, when, and how did it become one book?

Direct answer: the Bible is a library rather than a book, written by many people over roughly a thousand years in three languages — Hebrew, Aramaic and Greek — and assembled gradually into a single volume. Some of its writers name themselves; many do not. The text itself mentions two secretaries by name, describes one author's research method, and preserves several instances of an author taking the pen to sign a letter that someone else had been writing. The collection into one book was a process, not a decision: the earliest surviving lists that match today's New Testament date from the fourth century, and they record which books were already being read publicly rather than selecting new ones.

What does the Bible say about its own writing?

More than most readers expect, and in small, concrete details.

A secretary signs off inside a letter of Paul's, in Romans 16:

I, Tertius, who write the letter, greet you in the Lord. (Romans 16:22)

A prophet's words are written down by another man, in Jeremiah 36:

Then Jeremiah called Baruch the son of Neriah; and Baruch wrote from the mouth of Jeremiah all Yahweh’s words, which he had spoken to him, on a scroll of a book. (Jeremiah 36:4)

Paul takes the pen at the end of dictated letters: "This greeting is by me, Paul, with my own hand" (1 Corinthians 16:21), and more pointedly in Galatians 6:11, "See with what large letters I write to you with my own hand."

And one author states his method:

Since many have undertaken to set in order a narrative concerning those matters which have been fulfilled among us, even as those who from the beginning were eyewitnesses and servants of the word delivered them to us, it seemed good to me also, having traced the course of all things accurately from the first, to write to you in order, most excellent Theophilus; that you might know the certainty concerning the things in which you were instructed. (Luke 1:1-4)

That paragraph, in Luke 1, describes research: earlier accounts existed, eyewitnesses were consulted, the material was ordered. It is the closest thing the Bible has to a preface about its own construction.

Which languages was it written in?

Three. Most of the Old Testament is Hebrew. Sections of Daniel and Ezra, plus a verse of Jeremiah and a phrase in Genesis, are in Aramaic — the common language of the Near East under the Persian empire and the everyday language of first-century Judea. The New Testament is in Koine Greek, the ordinary Greek of the eastern Mediterranean rather than the literary Greek of the classical authors, and it preserves Aramaic words untranslated in places: talitha koum, abba, maranatha, and Jesus' cry from the cross.

That mixture is itself evidence about the writers. These are documents produced inside particular communities with particular languages, not a single text handed down whole.

Who wrote what, and how confident can we be?

None of this is a modern scandal. Origen, writing in the third century, said of Hebrews that God alone knows who wrote it. The distinction that matters for a reader is between what the text claims and what tradition attaches.

What does the Bible say about inspiration?

Two passages carry most of the weight, and they say slightly different things.

Every Scripture is God-breathed and profitable for teaching, for reproof, for correction, and for instruction in righteousness, that each person who belongs to God may be complete, thoroughly equipped for every good work. (2 Timothy 3:16-17)

For no prophecy ever came by the will of man, but holy men of God spoke, being moved by the Holy Spirit. (2 Peter 1:21)

Christian traditions read these differently — some as claiming verbal precision, others as describing a process in which human authors wrote as themselves — and the difference is one of the deep dividing lines in modern Christianity rather than a detail. What both verses describe is a relation between God and human writers, not dictation to a passive hand: the Bible's own portrait, in Luke 1 and Jeremiah 36, shows research and dictation to secretaries.

How did the separate books become one book?

In stages, over centuries, in two parallel processes.

The Hebrew Scriptures. Luke 24:44 reflects a threefold shape already in use: "all things which are written in the law of Moses, the prophets, and the psalms". The boundaries of the third section were still fluid in the first century.

The Christian writings. Paul's letters were being collected and circulated early — 2 Peter 3:16 already refers to them as a group. Lists of accepted books appear from the second century onward, with a stable core (the four Gospels, Acts, the major letters) and a contested margin (Hebrews, James, 2 Peter, 2 and 3 John, Jude, Revelation). The earliest surviving list that matches the twenty-seven-book New Testament exactly is the 39th Festal Letter of Athanasius of Alexandria, in 367, and North African councils at Hippo and Carthage in the 390s recorded the same collection.

Two things follow from that history. First, no council invented the Bible: the councils recorded what was already being read in the churches, and the criteria they applied were use, apostolic connection and consistency with the received faith. Second, the process was untidy, and it left different Christian traditions with slightly different Old Testaments — the subject of why the Catholic Bible has 73 books and the Protestant one 66.

What about the physical copies?

The books circulated as scrolls and then as codices, hand-copied for well over a millennium. Thousands of Greek manuscripts of the New Testament survive, along with the Dead Sea Scrolls for the Hebrew Bible, discovered from 1947 onward and including a copy of Isaiah roughly a thousand years older than the previously oldest complete Hebrew manuscripts.

Modern translations are made from critical editions built by comparing these manuscripts. Where they differ, most English Bibles record the significant variants in footnotes — which is a practice worth noticing, because it is the opposite of the claim, sometimes made in either direction, that the manuscript situation is being hidden.

The text published on this site is the World English Bible, a modern English translation in the public domain; the licensing details are on the translations and licenses page.

What the question usually presupposes

"Who wrote the Bible" is often really one of two other questions: whether it was written by God or by people, and whether it has been changed. The text's own answer to the first is that it was written by people, named and unnamed, whom the tradition understands to have been moved by God — the two are not presented as alternatives. The second question is a historical one with a large, public and checkable body of evidence behind it, and it is answered by manuscripts rather than by assertion in either direction.

Bible text: World English Bible (public domain). This article describes what the text says and what different Christian traditions teach; it does not recommend one of them.