Why was the old testment written?

Answer 1

A lot of unconnected people wrote bits of the Old Testament over a very long period of time. These people did not know each other and were probably just recording the traditional oral stories which had been greatly embellished over time to the point of making things sound like miracles. There was no early intent to have all of these writings collected into a single book.

Answer 2

The Old Testament was written to document the history and religious laws of the Israelites, as well as their relationship with God. It contains the foundational texts of Judaism and provides guidance on how to live a righteous life according to these beliefs.