The Septuagint and Mesoratic Text

The Septuagint was held with great respect in ancient times; Philo and Josephus ascribed divine inspiration to its authors. Besides the Old Latin versions, the LXX is also the basis for the Slavonic, Syro-Hexaplar (but not the Peshitta), Old Armenian, Old Georgian and Coptic versions of the Old Testament. Of significance for all Christians and for Bible scholars, the LXX is quoted by the Christian New Testament and by the Apostolic Fathers. While Jews have not used the LXX in worship or religious study since the second century AD, recent scholarship has brought renewed interest in it in Judaic Studies. Some of the Dead Sea scrolls attest to Hebrew texts other than those on which the Masoretic Text was based; in many cases, these newly found texts accord with the LXX version. The oldest surviving codices of LXX (Codex Vaticanus and Codex Sinaiticus) date to the fourth century AD.

The differences between the LXX and the MT thus fall into four categories.

Different Hebrew sources for the MT and the LXX. Evidence of this can be found throughout the Old Testament. Most obvious are major differences in Jeremiah and Job, where the LXX is much shorter and chapters appear in different order than in the MT, and Esther where almost one third of the verses in the LXX text have no parallel in the MT. A more subtle example may be found in Isaiah 36.11; the meaning ultimately remains the same, but the choice of words evidences a different text. The MT reads "...al tedaber yehudit be-'ozne ha`am al ha-homa" [speak not the Judean language in the ears of (or — which can be heard by) the people on the wall]. The same verse in the LXX reads according to the translation of Brenton "and speak not to us in the Jewish tongue: and wherefore speakest thou in the ears of the men on the wall." The MT reads "people" where the LXX reads "men". This difference is very minor and does not affect the meaning of the verse. Scholars at one time had used discrepancies such as this to claim that the LXX was a poor translation of the Hebrew original. With the discovery of the Dead Sea Scrolls, variant Hebrew texts of the Bible were found. In fact this verse is found in Qumran (1QIsaa) where the Hebrew word "haanashim" (the men) is found in place of "haam" (the people). This discovery, and others like it, showed that even seemingly minor differences of translation could be the result of variant Hebrew source texts.

Differences in interpretation stemming from the same Hebrew text. A good example is Genesis 4.7 shown above.

Differences as a result of idiomatic translation issues (i.e. a Hebrew idiom may not easily translate into Greek, thus some difference is intentionally or unintentionally imparted). For example, in Psalm 47:10 the MT reads "The shields of the earth belong to God". The LXX reads "To God are the mighty ones of the earth." The metaphor "shields" would not have made much sense to a Greek speaker; thus the words "mighty ones" are substituted in order to retain the original meaning.
Transmission changes in Hebrew or Greek (Diverging revisionary/recensional changes and copyist errors)