Why is the Bible divided into the Old Testament and the New Testament?

The Old Testament is about the history of the Hebrews and the behavior of the Holy Father in the Trinity. The New Testament records the story of the Son Jesus Christ, the development of the church in the early AD, the teachings of Christianity and the apocalypse.

2, language use is different:

The Old Testament is basically written in Hebrew (and a little Aramaic); The New Testament is written in ancient Greek (from a professional point of view, it is called New Testament Greek, which is greatly influenced by Semitic language).

3. Different time spans:

The Old Testament tells about 4000 years of history. The New Testament spans only a hundred years.

4. Different writing groups:

There are twenty or thirty authors in the Old Testament and only 10 authors in the New Testament. It is generally believed that the former took 1000 years to write, while the latter took about 5 or 60 years.