Who decided which 66 books would go into the Bible? Well, the short answer is God did. And, why 66 books? Why not 65 or 67? Again, it was God who determined the number of books that would make up the Bible. You see, the Bible is a Divine Book, not human.
- It is Divinely Inspired–II Timothy 3:16 “All Scripture is inspired by God.”
- It is of Divine Origin–II Peter 1:20-21 “No prophecy of Scripture is a matter of one’s own interpretation, for no prophecy was ever made by an act of human will, but men moved by the Holy Spirit spoke from God.”
- It Has and Will Stand the Test of Time–Isaiah 40:8 “The grass withers, the flower fades, But the word of God stands forever.”
In the same way God inspired men to write His Word, He also chose to use human instrumentality to gather the sixty-six books into one book that we call the Bible. The gathering of the sixty-six books that were considered to be inspired and authoritative did not come all at once. It was a result of many years of prayer, discussions and study by believers, churches and councils that finally arrived at universal agreement as to which books should make up the Bible. Those books which by the providence of God they came to agree on are the same sixty-six books you have in the Bible you hold in your hand today; no more and no less.
Very Likely the first written acceptance of the complete listing of the twenty-seven books of the New Testament came about in the year A.D. 377. Athanasius, the Bishop of Alexandria, wrote an Easter letter that contained all twenty-seven books of the New Testament, the same twenty-seven books we have in our New Testament today.
By about 200 years before Christ there was nearly universal agreement on the thrifty-nine books of the Old Testament.We know that the Old Testament was in existence and in use before Jesus’ earthly ministry because He often quoted from it. It was the Scripture that the apostles and early Christians used in their teaching, preaching and worship.
let’s take a brief look at the gathering of the thirty-seven books of the Old Testament. The first five books: Genesis, Exodus. Leviticus, Numbers and Deuteronomy were the first to be accepted as inspired and authoritative. These books, written by Moses later became known as the Pentateuch or the Torah. Likely it was Ezra and Nehemiah that fixed these five books once and for all as authoritative.
It was probably around 200 B.C. when the Prophet’s writings were brought together in a single form. The remaining Old Testament Books were collected and adopted as inspired Scripture sometime before the birth of Christ.
Jesus often used and quoted the Old Testament during His earthly ministry. One example was that of His forty days temptation in the wilderness. In a conversation with Satan, Jesus spoke to him at least three times using Scripture from the book of Deuteronomy: “Man shall not live on bread alone . . .”Deuteronomy 8:3; “You shall not put the Lord your God to the test” Deuteronomy 6:16; “You shall worship the Lord your God, and serve Him only” Deuteronomy 6:13.
Luke records the time Jesus visited a synagogue in His hometown of Nazareth. When invited to read Scripture, He searched through the scroll of Isaiah the prophet and read the prophet’s pronouncement of the coming Messiah. When Jesus finished reading, He set aside the scroll and said these remarkable words, “Today this Scripture has been fulfilled in your hearing.” There is no question, Jesus considered the Old Testament Books as the inspired and authoritative Word of God.
The Gospel writers often cited passages from the Old Testament, giving no question about their authenticity and authority. Matthew in particular often used Old Testament Scripture as he wrote about the life and ministry of Jesus, For example, Matthew 2:17 “Then what had been spoken through Jeremiah the prophet was fulfilled.” Matthew used that prophetic utterance written by the prophet in Jeremiah 31:15 to record the fulfillment of that Old Testament prophecy about the slaughter of children, two years-old and younger in and around the vicinity of Bethlehem, the place prophesied where the Messiah was to be born.
The New Testament writers never questioned the inspiration and authenticity of the Old Testament. It was their Bible. They quoted it, read and taught from it like we do our sixty-two Books of Scripture. We often hear them making reference to the Prophets like Isaiah, Daniel, Joel and Jeremiah as well as the Psalms and other Scriptures from the thirty-Seven books of the Old Testament.
For the New Testament, the process of recognition and collection began in the first centuries of the Christian church. Early on, some of the New 
Testament Books were being recognized as inspired and authoritative. For instance, Peter recognized the Apostle Paul’s writings as Scripture–II Peter 3:15-16 “And regard the patience of our Lord as salvation; just as also our beloved brother Paul, according to the wisdom given him, wrote to you, as also in all his letters . . .”
Some of the books of the New Testament were being circulated among the churches. See for instance, Colossians 4:16 and I Thessalonians 5:27.
Early Christians set certain criteria to decide whether a New Testament book was truly inspired by the Holy Spirit and should be included in the New Testament. Their criteria required the following:
- Was the author an apostle or have a close connection with an apostle?
- Is the book being accepted by the Body of Christ at large?
- Did the book contain consistency of doctrine and orthodox teaching?
- Did the book bear evidence of high moral and spiritual values that would show a work of the Holy Spirit?
It is important to remember that the church or a church council did not decide the Books that would make up the Bible. It was God who determined which books belonged in the Bible. It was the work of His sovereign design and His divine providence that brought the early church to recognize and accept the books He had inspired.
The Bible is God’s Book! It is undeniably His Holy Word to guide and direct us in this life and our eternal life to come.