Then why did Jesus quote the Septuagint, and not the Hebrew scriptures?
I didn't know that he did. I think that is it agreed that He spoke in Aramaic, but we have no Aramaic Gospels. Odd, that.
Since the writers of the Gospels, at least 10s of years and perhaps 100s of years afterwards, wrote in Greek, then it makes sense to include the quotation in Greek, and the Greek quotation to use would be the LXX.
To do otherwise would have a mishmash of Greek, Aramaic, and Hebrew. Which would have been close to the historical reality, but far from what the literature that we have. That was my main argument with Mel Gibson's movie: They introduced Pontius Pilate's Latin, to what was, almost certainly a situation where Greek would have been spoken.
My other nit was that all the conversations were very very slow. I don't speak Aramaic, but my very limited smattering of Arabic would have played much faster. So would my Latin, if I had not done it in Greek.
It is my belief that the Qu'ran was written hundreds of years after the putative Mohammed, for contemporary political reasons (to justify the conquest), using the letters developed for Syrio Aramaic, and quite a few Syrio Aramaic words, that had no counterpart in Arabic. At the same time Sufi Muslims (who wore poor quality wool garments as a mark of their piety) were protesting against the "Court Islam" of their day. They were inspired by the austerity of Syriac Christian Monks.
Minor Irony: The "traditional woman's head cover"
made mandatory by the religious nutballs in Iran was introduced in Lebanon, and patented in 1979 by a gentleman who hoped to mark Muslim women as not being suitable targets for rape by Muslim/Palistinian thugs, inspired by the headgear of Maronite Christian Nuns.