Bruce’s (truncated) quote appears on a number of Jewish web sites . The Bruce’s quote does not address the issue of the Septuagint being limited to the Torah prior to the time of Christ (although a number of comments attempt to make that claim). Note his words, "The Jews might have gone on at a later time to authorize a standard text of the rest of the Septuagint, …” Not Torah. The Septuagint already included all the books of the canonical Hebrew Scriptures by the time of Christ.
On the surface, he appears to be mainly speaking of the standardization and preservation of the Septuagint, not the original authorship nor the extent of that work. It’s pretty clear from the historical data that the Christians had a real hand in its preservation. I’m not aware of any quotes by Bruce on the Philo legend: 72 rabbis working in 72 days.
I believe the scholarly consensus today is that the Septuagint was completed in a period of about 2 centuries, beginning in 3rd century BC, and covered most if not all of the canonical Hebrews Scripture.
They knew that Isaiah was speaking about a married woman and that the "sign" wasnt a virgin birth but the age of the child.
And thus we get to the heart of the issue. Christ’s apostles (infallibly/inspired according to Christian doctrine) interpreted the OT prophecies and applied them to Christ. Christ was born of a true virgin, i.e., a woman who had not known a man sexually. Those who deny Christ within the Jewish community obviously have a vested interested in undoing the apostolic work as possible. No one should be surprised.
Might have...F F Bruce is acknowleging that there is serious problems with that premise. Noteably, the obvious differences in style, grammar, translation of the rest of the Septuagint from the Torah portion. If the Septuagint was uniform in structure throughout, you would have a point. It is not however.
And thus we get to the heart of the issue. Christ’s apostles (infallibly/inspired according to Christian doctrine) interpreted the OT prophecies and applied them to Christ. Christ was born of a true virgin,
Ha Alma means the young woman. There is no way to get vigin out of the text. Do you believe there was two virgin births? To be of any use to king Ahaz, who the text is trying to confer the prophecy, then there must have been two virgin births. That would therefore not be a unique event. It would also mean that there would be two god-man entities. The prophecy was not the birth of the child but the age of the child and his diet. Before he would reach the age of maturity and that he would eat well in times of plenty.
Also, the young woman would name him Immanuel. Jesus name in the greek is the Hebrew name Joshua. G-d saves. Not even close.