How the Old Testament came together
The Old Testament collection of books was translated into Greek by a number of scholars in Egypt around 200 BC. Around AD 100, a group of Rabbi (Jewish leaders, and nothing to do with bunnies) in Jamnia, Palestine, formally recognised the sacred Jewish writings of the Old Testament as the official version of the Hebrew Bible. The term for this official version is the “canon”.
The Dead Sea Scrolls contain a complete collection of the Old Testament (except for the book of Esther) and dating shows that they were produced between 150 BC and AD 50.
When Jesus was a child, he would have sat in the synagogue and listened to this collection being read out loud. Later, as an adult, he held the scrolls in his hands, read from them and taught in the synagogue.
How the New Testament came together
After Jesus died, rose back to life and ascended into heaven, many accounts about his life and teaching circulated. His followers spread out around the Mediterranean region, and gatherings of Christians continued to spring up everywhere.
The biographies of Jesus written by Matthew, Mark, Luke and John were doing the rounds. Paul’s letters to various churches and friends, in which he addressed issues about Christian teaching and living, were also doing the rounds.
By the 3rd Century AD, these documents were widely circulated and used by Christian communities as writings of great importance. There were, of course, other writings around at the time that were not held in such high regard. There were other documents about Jesus’ life, but they weren’t considered to have the same authority.
By the 4th Century, a collection of writings was recognised (or made into a 'canon') by two official gatherings of Christian bishops (leaders) at the Council of Carthage and the Council of Laodicea. Those writings are in your Bibles. They make up the New Testament.
It is not, as is claimed in the DaVinci Code” that the church determined which books were “in or out”. Rather, the church recognised which books were “in or out” based on their authority. A book is not the Word of God because it is accepted by the people of God. Rather, it is accepted by the people of God because it is the Word of God.
So why is there nothing after the New Testament?
The Bible itself puts it this way:
“In the past God spoke to our forefathers through the prophets at many times and in various ways, but in these last days he has spoken to us by his Son, whom he appointed heir of all things, and through whom he made the universe.” (Hebrews 1:1-2)
God has spoken definitively in Jesus. Jesus’ witnesses have written down what they saw and heard. There is no need for more evidence. No need for more letters. No need for more books. The Bible is complete. In it we have everything we need to know God, and to know Jesus. In it we have everything we need for life and godliness (2 Peter 1:3).