>> ““all scripture” means all scripture known to hellenized Jews at the time.” <<
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There have never been any “helenized” Jews living in the land of Caanan.
There were Greek speaking Jews in Egypt, and in the Greek isles, but that was simply because it was the majority language in those locations at the time. That has never been true of Caanan, as you can easily determine by reading the first two books of the Maccabees.
All things Greek were hated and rejected by Judah, even unto death.
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Timothy’s father was Greek. Doesn’t get more hellenized than that. And, why was the Septuagint and later the entire New Testament written in Greek?