You are leading yourself to the point. The translators agree with you that the LXX differs from the TR in many places ... but they went on to say that the apostles quoted from the LXX, the church fathers quoted from it ... they treated the LXX as the very word of God ... even though it differs with Hebrew texts. Read what they wrote ... its very enlightening.
And that's the point ...
That first conjecture, that the LXX is not the word of God ... should be seriously reconsidered. Men far greater in these languages than you and I have weighed in on this.
The apostles never saw the LXX, their writings were of Yeshua’s words, which were exact quotes of the Hebrew texts, not the LXX.
The LXX was injected when their original writings were translated into Greek. the translators used the Rabbis’ LXX instead of translating the actual words. This is something that Wescott and Hort discovered when they were doing their false Greek NT around 1850. Wescott’s son revealed their devious letters after his father died. Gail Riplinger went through the letters when researching her first book.
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