The Old Testament (abbreviated OT) is the first part of Christian Bibles, based primarily upon the Hebrew Bible (or Tanakh), a collection of ancient religious writings by the Israelites believed by most Christians and religious Jews to be the sacred Word of God. The second part of the Christian Bible is the New Testament.
The first part of the Christian Bible, comprising thirty-nine books and corresponding approximately to the Hebrew Bible. Most of the books were originally written in Hebrew, some in Aramaic, between about 1200 and 100 BC. They comprise the chief texts of the law, history, prophecy, and wisdom literature of the ancient people of Israel.