The Old Testament is not a science textbook and neither is the New Testament, so in this respect they are the same. Also there is no difference in that the 66 books of which they both comprise are to be received as the authoritative inspired written word of God. Moreover the message is the same that God loves His Creation and desires that every man and woman comes to the knowledge of the truth and takes up the inheritance that rightfully belongs to each one. If the inheritance is forsaken then eternal life is forsaken and each one will have to bear the guilt of his or her own sin. The Old Testament comprises of 12 more books than the 27 books of the New Testament. The Old Testament as accepted by most non-Catholics consists of the books that are accepted by the Jews as the inspired written word of God, which include the only words ever recorded to have been written by God Himself.
The Old Testament records God's plan for this present Earth as shown to Moses and expounded upon by the prophets. It also records the outworking of the plan to bring about the Savior of the World who redeems what the first man Adam lost. This plan was exemplified in the deliverance of Israel from Egypt. In this respect the Bible is a reliable historical document, even if fools reject the abundant archaeological evidence that verifies this. For not only is there an abundance of verifiable archaeological evidence that testifies to the Exodus and the whereabouts of Mount Sinai and Mount Horeb, there is also evidence for Noah's Ark and the cities of Sodom and Gomorrah and much more.
One of the features of the Old Testament is how often reference is made to the deliverance of the nation Israel from Egypt. Many times the nation Israel is referred to rather than the individual.
The Old Testament testifies to Lord Jesus Christ. The Apostles used the Old Testament to teach about Lord Jesus Christ in the first century after His death, while the New Testament was being composed.
The New Testament is a written record of what Jesus stated comprising of four gospels for different reasons, a historical record, epistles and a prophetic book. The book of Acts and the Gospel of Luke are a historical record of what happened during the days of Jesus and the apostles; they were authored by a medical practitioner. The Apostle Paul wrote most of the Epistles, except for Hebrews, James, Peter, John and Jude. These epistles provide insight into the Old Testament and the manifestation of Word of Life that was with the Father from the beginning. The Book of Revelation is a book of prophecy that gives an indication of the seven eras of the Church Age and what shall take place in the last days once the Laodicean era has produced a church that has become so worldly that distinguishing it from the secular is close to impossible.
The differences between the two testaments is often summed up as the Old Testament being the New Testament concealed and the New Testament is the Old Testament revealed.
However, while it is true in many respects that the New Testament is a revealing of the hidden purpose of God within the Old Testament, not everything is revealed so readily. Only by walking with God is a person able to learn the truth and demonstrate this knowledge in his or her life. In this respect, the New Testament tends to refer to the individual more than the Old Testament. This is because the New Testament appeals more to the Gentile nations than what it does to the Jew.
In the main the differences between the Old Testament and the New Testament have to do with the era they were written, with one book being canonized by the Jews and the other being canonized by Christians. Nevertheless, for those who understand the significance of the Mosaic Covenant and the many types therein, the 66 books of the Bible are typed in the ornamental flowers, buds and knops of the lamp stand that was placed on the table opposite the show bread in the Holy Place.