I found much to agree with in the article from De Trefethen, but the "Last
Day" of the Feast of Tabernacles is not the 8th day. It is the seventh day. The
8th day follows the "great, last day." This makes sense because the 8th day is
a picture of eternity, while the 7th day is a picture of the 1,000 year rest.

As mentioned in the article, God specified the Feast like this:

Lev 23:34 Speak unto the children of Israel, saying, The fifteenth day of
this seventh month [shall be] the feast of tabernacles [for] seven days unto the
LORD.

Lev 23:41 And ye shall keep it a feast unto the LORD seven days in the year.
[It shall be] a statute for ever in your generations: ye shall celebrate it in
the seventh month.

There are only two books in the Bible that mention the "last day." One is the
Gospel of John, and one is Nehemiah:

Neh 8:17 And all the congregation of them that were come again out of the
captivity made booths, and sat under the booths: for since the days of Jeshua the
son of Nun unto that day had not the children of Israel done so. And there
was very great gladness.

Neh 8:18 Also day by day, from the first day unto the last day, he read in
the book of the law of God. And they kept the feast seven days; and on the
eighth day [was] a solemn assembly, according unto the manner.

The Feast itself is seven days long. They live in booths for seven days. The
"last day" is the last day of the Feast - the seventh day. The 8th day is a
special day and comes after the last day of the Feast.

Here is a non-Christian Rabbi saying the same thing:

http://www.myjewishlearning.com/holidays/Sukkot/Overview_Sukkot_Intermediate/Hoshanah_Rabbah.htm

LLee