What was the writer of Hebrews quoting, since it was not the Hebrew?
The writer to the Hebrews in Heb 1:6 quotes from Deut. 32:43 and writes the words: "And let all the angels of God worship him."
"And again, when he bringeth in the firstbegotten into the world, he saith, And let all the angels of God worship him." (Heb 1:6, KJV)
The TSK cross reference for the underlined above reads: De 32:43; Sept:
When you go to the KJV of Deut 32:43, from the Hebrew, you cannot find that sentence underlined above.
"Rejoice, O ye nations, with his people: for he will avenge the blood of his servants, and will render vengeance to his adversaries, and will be merciful unto his land, and to his people. (Deut 32:43, KJV)
Paul, if he wrote Hebrews, was quoting the LXX, the Septuagint which includes that sentence:
"Rejoice, ye heavens, with him, and let all the angels of God worship him; rejoice ye Gentiles, with his people, and let all the sons of God strengthen themselves in him; for he will avenge the blood of his sons, and he will render vengeance, and recompense justice to his enemies, and will reward them that hate him; and the Lord shall purge the land of his people." (Deut 32:43, LXXE)
What recognized authority or respected reference work states that the Septuagint did not exist?
The Encyclopedia Brittannica gave a lot of space for a translation that did not exist.
https://www.britannica.com/topic/Septuagint