The Masoretic Text is the definitive text of the Hebrew Bible. It was primarily  edited, fixed and standardized from old Hebrew manuscripts by a group of Jewish scholars known as the Masoretes or Masorites in Tiberias, Israel, between the 7th and 10th centuries C.E.  The purpose of these scholars or rabbis was to safeguard the authenticity of the original Word of God. These manuscripts had been compiled and set in order by Levite scribes after the return of the Jews from Babylon to Palestine under the leadership of Nehemiah and Ezra. The Masoretes’ main purpose was to correct any faults that had crept into the text during the Babylonian captivity and to prevent its being corrupted in the future by any alterations. The Dead Sea Scrolls, discovered at Qumran in 1947, show an amazing consistency with the Masoretic Text; about a third of the scrolls are indistinguishable from Masoretic texts written a thousand years later. It is thus evident that God, Himself, had supervised and protected His Word throughout centuries of copying. 

The Septuagint was translated mainly for the Hellenistic or Greek Jews who did not return to Palestine. These Jews spread throughout the empire and had for the most part lost their Hebrew language. The Septuagint Greek Old Testament was begun and funded by Ptolemy II Philadelphus (B.C. 286-245). It had its origins in Alexandria, Egypt, and was the work of 70 or 72 Jewish scholars, hence the name Septuagint, which means seventy in Latin. This Greek translation contains the standard 39 books of the Old Testament as well as the Apocrypha (a term coined by Jerome in the 5th century A.D., and which refers to ancient Jewish writings penned during the period between the last book of the Jewish Scriptures, Malachi, and the advent of Christ).  Although included in the Septuagint for religious and historical reasons, these books or Apocrypha are not regarded by Protestant Christians or Orthodox Jews as canonical (inspired by God).