After Jesus' ascension, the disciples went around teaching and building the church by personal presence and sometimes writing a letter. The apostles first priority was to deliver a personal testimony to the facts of the gospel (good news). Their teaching was oral. But as time progressed, and there became more and more congregations, the necessity for written teachings became apparent. The Old Testament existed for study, but there was no official text available for study about this new 'Jesus movement'. Soon, the gospels came into existence, two written by apostles, and two written by close friends of apostles. Next the letters of various apostles which had been circulated and collected for study and re-reading became important to the growing congregations. As the persecution of the Romans under Diocletian (about 300 A.D.) increased, and other false and spurious gospels and letters appeared, the need for a list of official genuine books was required. This resulted in the development of the New Testament canon. (See New Testament - Origins) for more details.
The New Testament then consists of four classes of literature:
The earliest writings in the New Testament are the letters written to the various Christian churches, answering matters of practice and belief. Paul wrote most of these between 52 A.D. and 64 A.D.. The first is considered to be the letters to the Thessalonians.
The New Testament is a great place to begin reading the Bible because it starts with the story of Jesus and His teachings. Understanding this, the rest of the Bible comes into perspective.