Recently a missionary confronted R' Tovia Singer accusing the rabbi of deception, writing
"In a show about the divorce of Israel, comparing the quote from the book of Hebrews and the quote from Jeremiah 31 (about the new covenant G-d will make with the Jews in the messianic age) it is not the fault of the author of Hebrews, rather, it is an issue with the Septuagint. . . I am surprised that Tovia PRETENDS not to be aware of this."(see link to video at bottom of post).
The Septuagint did not include the book of Jeremiah. Apparently the missionary was unaware of this not so minor detail.
The Septuagint was a translation from Hebrew into Greek only of the Torah (Five Books of Moses). Over time other books of the bible were translated into Greek, including Jeremiah -- but who translated them and when is unknown. What IS known is that over time the Greek translations of the T'nach (Jewish bible) were maintained by Christians long after Jews stopped using them and they became more and more corrupt.
In other words, what a Greek translation (ancient or not) of Jeremiah says is immaterial -- no one knows who translated it or when and we do know that even the Christians know these Greek translations were corrupt. Over time various Greek translations of books not part of the Septuagint came to be CALLED the Septuagint.
So when you hear of the Septuagint of Jeremiah, Isaiah or other Prophets or Writings they were not actually part of the Septuagint -- it is just that over time people began calling them by the name "Septuagint" or "LXX."
Speaking of Jeremiah in what is called the Septuagint:
". . . the Greek text itself is uneven, an unevenness which in the past has led scholars to posit that the two parts of the LXX (1-28 and 29-51) were prepared by two different translators. Recently it has been proposed, with persuasive arguments, that the second half of the Greek translation is a revision of an earlier translation, the so-called Old Greek text, the latter having survived only in the first half of the text of the (so-called Septuagint) LXX." [Craige, Kelley, & Drinkard, WBC]
Sticking with Jeremiah, Jeremiah 23.7-8 comes after 23.40 in what has come to be called the Septuagint (so some copiest "moved" it). Anyone considering the Greek translations which are called the Septuagint as reliable is deluding himself (or herself).
Origen, an early church father (died 232 CE), tried to piece together a decent translation of the Hebrew Bible by putting 6 different versions side by side (called the Hexapla) which included what the so-called Septuagint (including things never in the real Septuagint such as Jeremiah and Isaiah). He wrote:
"we are forthwith to reject as spurious the copies in use in our Churches, and enjoin the brotherhood to put away the sacred books current among them, and to coax the Jews, and persuade them to give us copies which shall be untampered with, and free from forgery! Origen, A Letter from Origen to Africanus, Ante-Nicene Fathers, Volume 4.
The missionary wonders if the word "husband" could be mistaken for the Christian choice of "disregarded." Nope. The Hebrew word בָּעַ֥לְתִּי / "ba'altee" means a "husband." It in no way can be translated as "to disregard." The Christian Bible just totally ignores the REAL meaning of the words of Jeremiah. To be a "husband" is the precise opposite of "disregarding." In Hebrew the word for "disregarded" begins with a gimmel (ג) whereas the word for husband begins with a bet (בָּ). They are not similar -- just another missionary attempt to deceive and confuse. The word בָּעַ֣לְתִּי also appears in Jeremiah 3:14.
It is silly to say a gimmel could be confused for a bet -- because words are parts of sentences and in context the word "disregarded" is senseless. Just as words ending in "at" in English could be "cat" or "bat" or "sat" so too changing a letter here or there can change the meaning of a word in Hebrew. This missionary claim has absolutely no substance, let alone "proof."