The Old Testament canon in the Protestant Bible includes 39 books. Along with the 27 books of the New Testament canon, there are 66 books in total.
The 39 books were collected into the Old Testament canon as the people of God recognized which books were the actual word of God and which books may be helpful to read, but were not divinely inspired. The final collection of Old Testament books recognized by Protestants to be "God breathed" (see 2 Timothy 3:16) are the 39 Old Testament books found today in the Protestant Bible. The modern day Jewish Bible is also limited to these same 39 books. (In the Jewish Bible, however, several of these 39 books are combined together, making a total of 22 books.)
The formation of the canon must be seen as a process rather than an event. It was not formed by the declaration of a church council or other organization of influential people. Rather, as written revelation came from God through God's chosen writers, the people of God recognized God's voice and affirmed that the writing was indeed the word of God. Jesus said, "His sheep follow him because they know his voice" (John 10:4). The people of God knew the word of God when they heard it and read it and, as a result, the 39 books of the Old Testament were recognized and collected into the canon.
It should be noted that soon after the beginning of the Protestant Reformation the Roman Catholic church, at the Council of Trent in A.D. 1546, officially declared 12 additional books to be part of the Old Testament canon. These books were written during the 200 years immediately before the time of Christ and, while many of these books were considered helpful by the Jewish people, they were not considered canonical. These 12 books are sometimes referred to as the Apocrypha, though the term used by Roman Catholics is deuterocanonical, which means "later added to the canon." (The prefix deutero- means "second".) The collection of books called the Apocrypha includes 15 books in total, but the Roman Catholic church approved only 12 of these 15 books.
The Bible itself gives evidence that as the Old Testament books were written, they were quickly recognized as the word of God. Several examples are given below.
Exodus 24:3 teaches us that the writings of Moses were immediately recognized as the authoritative word of God:
When Moses went and told the people all the Lord's words and laws, they responded with one voice, "Everything the Lord has said we will do." Moses then wrote down everything the Lord had said.
Daniel 9:2 tells us that Daniel recognized the words written by the prophet Jeremiah as the word of God:
In the first year of his [Darius'] reign, I, Daniel, understood from the Scriptures, according to the word of the Lord given to Jeremiah the prophet, that the desolation of Jerusalem would last seventy years.
Jeremiah 26:17-18 shows us that the elders of Israel, as well as Jeremiah who was recording their words, recognized the writing of Micah as the word of God:
Some of the elders of the land stepped forward and said to the entire assembly of people, "Micah of Moresheth prophesied in the days of Hezekiah king of Judah. He told all the people of Judah, 'This is what the Lord Almighty says. . .’"
E. J. Young has concluded:
All the evidence supports the position that the books of the Old Testament, being of divine inspiration, were consequently authoritative, and were recognized as such from the time of their first appearance ("The Canon of the Old Testament" in Revelation and the Bible, Carl F. Henry, ed. Baker Book House, 1958, p. 162).
Thus, as soon as God "breathed" a writing, it was canonical; that is, it was God's standard of truth and rule for life. God's people recognized the writing as canonical, and they began the process of collecting and preserving these writings for future generations. By the time of Jesus, the 39 books of the Old Testament were collected and accepted by the Jews as the Old Testament canon.
