Why can't Christians Verify Exactly Where Jesus Was Buried?

[Aractus]

It's not at all based on the structure of the Septuagint. The LXX does not appear anywhere in history as a structured, organised, complete collection of the Hebrew scriptures until the 3rd century AD (as the fifth column of the Hexapla). You aren't entitled to make stuff up - all that we know for sure existed when Jesus was alive was some earlier version of the Pentateuch that later became the LXX (and possibly, if not probably, Isaiah and the Psalms as well). Like I keep saying, some proto-lxx that we don't know much about, other than the fact that it contained the Pentateuch. What you call the LXX is a collection of translations done at separate times by separate people and collected as a single library (and then later bound as a codex).

And again, the Greek vocabulary does not mean anything. Some gospel writers did use a proto-lxx, but not all did. There are several instances where the text exactly matches the Hebrew against the LXX. Luke for examples quotes from the Hebrew Pentateuch, and not the LXX Pentateuch. At other times he quotes from some proto-lxx version of Isaiah and Psalms. Matthew on the other hand, does appear to make use of some proto-lxx Pentateuch. So when Matthew quotes Jesus quoting the Pentateuch it's from the LXX, and when Luke does it it's from the Hebrew. Conclusion: the gospel writers have redacted the citations.

Anyway, the Sermon on the Mount is not too long or convoluted for a preacher in ancient times to remember. It may not be a single sermon, and it may be made up of two or more separate sermons that Jesus gave - that hardly worries me as an atheist. Like I said before, Jesus probably peached the Sermon or Sermons several times to several different audiences, and for those who repeatedly attended (like the disciples) remembering it wouldn't have been too difficult. After all they are meant to be taught by these Sermons.