@ TheRationalizer
could you please provide a link to that forum where you posted your question and save us your brilliant analysis?
Anyway, I just contacted an orthodox Jew myself and waiting for his reply.
I didn't get this from a Jewish forum, I just read it today in the Quran. The discussion in the forum hasn't revealed anything of use at all except the dates that the Talmuds were created - it's gone right off topic, but here it is anyway:
http://www.hashkafah.com/index.php?/topic/65220-oldest-physical-babylonian-talmud/Now, regarding Kathir, it is also what Yusuf Ali says (copy/pasted) - do you have any other Tafsir comments on this verse?
The verse looks pretty clear to me.
"Again, We gave the Scripture unto Moses,
complete for him who would do good, an explanation of
all things,"
What is clear is that the Jerusalem Talmud (which also contains a very similar statement) was finalised a long time before Muhammad's birth so no accusation can be made that the jews copied the Quran. Combined with this verse in the Quran it looks as though you can't fall back on the "Maybe god revealed it to them" argument either.
However if you have other tafsir comments on this verse then I would like to see them.