Why are there two testaments?

The Bible is the record of the Hebrew people and the early Christians.  Thus, we have two kinds of testaments or covenants.  The historically older belief system of the people of Israel, was written from around 1,000 BCE to around 150 BCE.  On the other hand, the newer testament or covenant was written between 50 CE and 125 CE.  However, both testaments or covenants have a common base in the Hebrew Scripture.

Human Authors

The Bible is the record of the Hebrew people and early Christians.  These human authors worked under the influence of God’s Spirit and at the same time under the influence of their community and culture.  Why these words?  Christians believe that this is God’s meaning in human words in content and message.  The cultural history and empirical science was true for their particular time.  History is always an interpretation.  Science is always experimenting finding new ways to do things.  The divine message of God transcends time and space, since it has an eternal ring to it that goes beyond the human authors and their words.