What is the LXX and why is it so noteworthy that there is a Greek translation of the OT? Wouldn't it be better to directly reference manuscripts in the original languages?
Before 1947, a good case could be made that the Septuagint represented a more ancient tradition than the Masoretic versions of the Tanakh. Since the Septuagint was produced before 132 BCE (and probably in the 3rd century BCE) and the earliest known Masoretic manuscripts date to the 10th century CE, the Greek translation might have fossilized an early rendering of the Scriptures while the Hebrew continued to be copied and potentially altered. To further support the primacy of the Septuagint, the early Christian and Hellenistic Jewish texts, tended to use that translation rather go back to Hebrew sources.
An interesting counter-argument arises from the observation that during the 600 years from Jerome's translation into Latin (the Vulgate) to the earliest Masoretic manuscripts, the Hebrew seems to have been faithfully copied. That suggests that Jewish scribes were exceptionally careful to duplicate their scriptures.
After 1947, the evidence changed. According to Wikipedia:
[Most] of the Qumran fragments can be classified as being closer to the Masoretic text than to any other text group that has survived. According to Lawrence Schiffman, 60% can be classed as being of proto-Masoretic type, and a further 20% Qumran style with bases in proto-Masoretic texts, compared to 5% proto-Samaritan type, 5% Septuagintal type, and 10% non-aligned. Joseph Fitzmyer noted the following regarding the findings at Qumran Cave 4 in particular: "Such ancient recensional forms of Old Testament books bear witness to an unsuspected textual diversity that once existed; these texts merit far greater study and attention than they have been accorded till now. Thus, the differences in the Septuagint are no longer considered the result of a poor or tendentious attempt to translate the Hebrew into the Greek; rather they testify to a different pre-Christian form of the Hebrew text".
Another another article describes the meaning of the categories in detail.
A few caveats are in order:
Surveying the Qumran about religious texts seems something akin to surveying a hippie commune about political issues—you're likely to experience some bias. If we could obtain a similar collection from Jerusalem, we'd likely find more agreement and likely the side of MT. Given the diversity in non-Scriptural texts, 60% seems quite solid support.
While it's unlikely, there exists a chronological possibility the scrolls associated with the Septuagint-aligned Hebrew were influenced by the Greek. (Any references one way or the other would be appreciated.)
What remains therefore is a window into the community of Alexandrian Jews that produced the translation. For those who are interested in the development of Jewish belief, that can be extremely useful. N. T. Wright's book, The Resurrection of the Son of God, shows that the LXX translators chose to interpret key texts from Daniel and Ezekiel about the resurrection as literal rather than metaphorical. He argues from this that belief in bodily resurrection was more common in Jesus' day than other scholars assert.
The Septuagint (LXX) was the version of the Bible used by the authors of the New Testament. Therefore, the authors sometimes quote the Septuagint rather than the Masoretic (Hebrew) text.
Matthew 1:23 NRSV "Look, the virgin shall conceive and bear a son, and they shall name him Emmanuel," which means, "God is with us."
The Masoretic Text of this quoted verse in Isaiah:
Isaiah 7:14 NRSV
Therefore the Lord himself will give you a sign. Look, the young woman is with child and shall bear a son, and shall name him Immanuel.
The difference is pretty striking.
Because of this, the translators of some versions of the Bible tend to use the Septuagint in the Old Testament.
The Septuagint text from that same verse:
Isaiah 7:14 ESV
Therefore the Lord himself will give you a sign. Behold, the virgin shall conceive and bear a son, and shall call his name Immanuel.
Ultimately, the Septuagint is useful to help gain an understanding of why the authors of the New Testament used quotes that they used. It helps clarify understanding of how the Greek was used.
One of the most important aspects of the Septuagint is that it helps us understand how Greek was used by Jews in the 3rd century BC to talk about God and the Scriptures. This turns it into a valuable tool to look at the Greek of the NT and understand how to translate and examine it.
Here is an excerpt from a Christianity.SE answer that I provided to illustrate one use of the Septuagint in this manner:
This document should shed some light on the usage of the word porneia and the Greek word family it belongs to.
Here is an excerpt from the conclusion: "In this study we have looked at the word family -porn- in extra-biblical Greek literature, in the OT, and in the NT. In all sources, porneia and the related terms refer to sexual acts only. Both OT and NT correspond largely when it comes to the word family. Though the OT favors the figurative sense and the NT the literal meaning, the different aspects of porneia are found in both testaments. They include prostitution, premarital sexual relations, adultery, incest, and homosexuality, in short, sexual relations outside of the marriage. Thus, OT and NT enlarge the understanding of fornication as found in the Greek world."
The bottom line is that the Septuagint and the NT have close agreement on the term. If you recall that the Septuagint dates back to the 3rd century BC, giving us an idea of how Greek was used and translated in relation to Hebrew. The agreement between the usage of this word in the NT and the Septuagint provides strong evidence to the colloquial use in those times.
The reason I most often use the LXX is to find the concept the NT authors were using. Yes, they wrote in Greek, but they were thinking Jewish thoughts. Many times, you can take the Greek words in the NT, find them in the LXX, and see what Hebrew words they translated.
For example, the word ecclesia is used in the NT in Matthew 16:18 and 18:17. Some argue that this means Matthew is written late because Jews in the time of Jesus would not use the concept of ecclesia. Patently false. If you check the LXX, you find the word ecclesia commonly translates qhl, which means "sacred assembly." And that means 2 things. 1) As the LXX was translated centuries before Christ, Jews were familiar with the concept of ecclesia and used it. 2) Matthew's use of ecclesia does not mean it is late.
One should not dismiss the Septuagint simply because it’s a translation, although all translations are imperfect. Languages simply can't be mapped one-to-one.
The project was undertaken by 72 Jewish scholars with the approval of the Sanhedrin and the High Priest in Jerusalem. There were about a million Greek-speaking Jews in Alexandria alone at that time, so creating a reliable Greek translation would have been a high priority in the Jewish community. Note that the project took about 100 years to complete, and as in all documents, there are variations as well.
As mentioned, the New Testament quotes of the Tanakh come from the Septuagint, and we can trace some of the disparities, and there are disparities between the Masoretic text and earlier texts. The primary checkpoints for variants and translations are the Greek Septuagint, the Dead Sea Scrolls, the Latin Vulgate, and the Hebrew Masoretic text. The Syriac Peshitta should also be taken into account. Emanuel Tov, emeritus Professor in the Department of Bible at the Hebrew University of Jerusalem and Editor-in-Chief, International Dead Sea Scrolls Publication Project, made this point clear in his 2006 lecture, “Exploring the Origins of the Bible.” In this presentation, Dr. Tov compared several selected passages in the Masoretic text, the Septuagint, and the Dead Sea Scrolls. For example, he notes that in Deuteronomy 32:43, Psalm 29, and Psalm 82, references to “the sons of God” and the “divine assembly” are present in the Septuagint and the Qumran scrolls, but were, in his words, “probably removed from the Masoretic text in an act of theological editing.”
The Hebrew scripture that Jesus quoted as recorded in John 10:31-39 was later revised to read “godlike beings” in the Hebrew version.
Rabbi Simeon ben Pazi, who lived in the third century CE calls the variant readings of his time "emendations of the Scribes" (tikkune Soferim; Midrash Genesis Rabbah xlix. 7). Christian scholars made similar observations. Here’s the earliest example.
“But I am far from putting reliance in your teachers, who refuse to admit that the interpretation made by the seventy elders who were with Ptolemy of the Egyptians is a correct one; and they attempt to frame another. And I wish you to observe, that they have altogether taken away many Scriptures from the translations effected by those seventy elders who were with Ptolemy . . .” – Justin Martyr, Dialog with Trypho, Chapter 71, ~150 CE
Around 130 CE, the Septuagint was renounced by the Jewish religious leadership in favor of other versions. The evidence seems to indicate that this was because the Septuagint had become widely used by Jewish and Gentile Christians to argue that Y’shua min Natzaret was the promised Messiah of prophecy after all.
IMO it is a mistake to consider the LXX too noteworthy. The NT authors quote from it under the inspiration of the Holy Spirit, however that should not be taken to imply that the LXX translation as a whole is inspired.
Wouldn't it be better to reference the Hebrew original?
Yes, except when dealing with the NT quotations in question. And translators are making a mistake if they use the LXX as an authoritative basis for translating the old testament even for those passages quoted in the NT
Of course none of this is to say the LXX is not useful as it may shed light on translation issues, as mentioned in other answers.
I will deal with one of the most important points is that The LXX writers preserved God's personal "name Jehovah in the Greek text:-
Mugridge concludes that early Gentile Christians could write the tetragrammaton in their homemade copies, but that later Christians "replaced the Tetragrammaton by Kyrios, when the divine name written in Hebrew letters was not understood any more." According to Edmon Gallagher, a faculty member of Heritage Christian University, some Christian scribes "would have produced a paleo-Hebrew Tetragrammaton", concluding that "if the scribe copied poorly the paleo-Hebrew script... as πιπι, which can be a corruption only of the Tetragrammaton in square script." Jerome wrote that by 384CE, some ignorant readers of the LXX assumed the tetragrammaton to be a Greek word, πιπι (pipi), suggesting its pronunciation had been forgotten, but affirming its existence at the end of the 4th century. Professor Robert J. Wilkinson suggests that Jews in mixed communities would not tolerate articulations of the tetragrammaton, and that Gentiles would have trouble pronouncing it if it were not ΙΑΩ or Κύριος. Some Jews may have continued to pronounce YHWH in one form or another, (e.g., ιαω in Greek) until the late of Second Temple Period. According to Pavlos Vasileiadis, a Doctor of Theology at the Aristotle University of Thessaloniki, "The indications denote that it was 'still being pronounced by some Hellenistic Jews' and also by non-Jews as late as the third century C.E."
Sidney Jellicoe concluded, "Kahle is right in holding that LXX [Septuagint] texts, written by Jews for Jews, retained the divine name in Hebrew Letters (paleo-Hebrew or Aramaic) or in the Greek-letters imitative form ΠΙΠΙ, and that its replacement by Κύριος was a Christian innovation". Jellicoe cites various scholars (B. J. Roberts, Baudissin, Kahle and C. H. Roberts) and various segments of the Septuagint, concluding that the absence of Adonai from the text suggests that the insertion of the term Κύριος was a later practice; that the Septuagint Κύριος is used to substitute YHWH; and that the tetragrammaton appeared in the original text, but Christian copyists removed it."-https://en.wikipedia.org/wiki/Names_and_titles_of_God_in_the_New_Testament
PROOF THE NAME JEHOVAH WAS IN THE 1ST CENTURY SEPTUAGINT LXX Was God's personal name JEHOVAH in the first Century Septuagint?
Swete's Intro to the OT in Greek, chapter 2.6.5: "The Tetragrammaton is not transliterated, but written in Hebrew letters, and the characters are of the archaic type , not יהזה cf. Orig. in Ps. ii., καὶ ἐν τοῖς ἀκριβεστάτοις δὲ τῶν ἀντιγράφων Ἐβραίοις χαρακτῆρσιν κεῖται τὸ ὄνομα, Ἐβραικοῖς δὲ οὐ τοῖς νῦν ἀλλὰ τοῖς ἀρχαιοτάτοις —where the 'most exact copies' are doubtless those of Aquila's version, for there is no reason to suppose that any copyists of the Alexandrian version hesitated to write Ο ΚΣ or ΚΕ for (יהזה)” HERES THE EVIDENCE TO PROVE IT! Foead 266 1st century B.C. The Foead-papyrus collection (Foead; inv. n° 266) is in possession of the Société Egyptienne de Papyrologie in Caïro. This collection is dated from the 1st century B.C. The collection was discovered in Egypt in 1939 and includes parts from the Bible books of Genesis and Deuteronomy. The Name cannot be found in the Genesis fragments, because the text is incomplete. But, in the book of Deuteronomy, in the midst of the Greek text, it is written 49 times in Hebrew characters. The Tetragrammaton can be found three more times in fragments that are not identified (fragments 116, 117 and 123). IIn a commentary on this papyrus collection Paul Kahle wrote in 'Studia Evangelica', edited by Kurt Aland, F. L. Cross, Jean Danielou, Harald Riesenfeld and W. C. van Unnik, Berlin 1959, page 614: “A distinguishing characteristic of the papyrus is the fact that the name of God is written as the Tetragrammaton in Hebrew square-shape [(יהזה)]. Upon my request made for an examination by father Vaccari in regards to the published fragments of the papyrus, he came to the conclusion that the papyrus must be written 400 years before the codex B, probably the most perfect text of the Septuagint that has reached us".
There are some significant reasons why one should care about the Greek Translations of the Old Testament.
- The Greek manuscripts are hundreds of years closer to writing than the Hebrew manuscripts.
- Building upon the above, the Greek provide some reading not preserved in the later Hebrew.
- The Greek manuscripts provide translations and interpretations of words that appear only a couple times in Hebrew.
- The Greek provide the vocabulary and background for the Greek NT.
- New Testament authors usually quote from one of the Greek translations.
Edit: Let me provide some examples of point 2, from my research. In Zechariah 11:14, the broken staff annuls the κατάσχεσιν in the Greek. This corresponds to the Hebrew הָאְַחֻזַּה, "possession," while the Hebrew manuscripts only attest to הָֽאַחֲוָה, "brotherhood."
Another example can be seen in Zechariah 12:3, which reads καταπατούμενον, in the Greek. This corresponds to the Hebrew, מִרְמָסָה, "a stone which is stepped on." However, Hebrew manuscripts only provide the reading, מַֽעֲמָסָה, "a burdensome stone."
Finally, in Zechariah 13:1, the Greek reads "a place (τόπος) will be opened." The Hebrew reads "a fountain will be opened." The difference in Hebrew is a mere letter between מָקוֹם and מָקוֹר.
Overall, there are many instances like the ones I have cited. While the readings exist in Greek, that doesn't mean that a Hebrew text accompanied it. There may have been a mistake in reading the letters. It is thus the scholars role to evaluate each reading in context, to see which reading is likely original.