The 7th day of the Feast of Tabernacles
The Great Last Day
not Shemini Atzeret which is the day "after" the 7th Day of the Feast.
The 7th day of the Feast of Tabernacles "is" The Great Last Day, "because" it "STARTS" THE GREAT 1000 YEARS of Christ Jesus'/Yeshua's GREAT reign.
We "know" that the 7th Day of the Feast "is" The Last Great Day, "because" it was the day that Jesus stood up "on" the last day of the water oblation ceremony, where the Priests went 7 times round the Altar (on the 1st Day of the Feast the Priests only went 1 time around the Altar, 2nd Day = twice, etc.) and poured water on the horns of the of the Altar. I will raise him up on the LAST DAY John 6:44.
The Great Last Day is "BEFORE" the start of the 8,000th year, because Jesus/Yeshua spoke of water "during" the 7th day of the water oblation ceremony on the 7th day of the Feast.
And Jesus then stood up (on the Great Day of the Feast) and said: If any man thirst, let him come to "Me" and drink. John 7:37.
The day that Jesus raises all the Dead is at "the end" of the 7,000th Year (not the beginning); and the rest of the dead were not raised until the end of the 1000 years. But the rest of the dead did not live again until the thousand years were finished. Revelations 20:5.
Then, once raised, there is 100 years for the person to repent. Isaiah 65:20.
The 7th Day of the Feast of Tabernacles "is" The Great Last Day because it is the "GREAT Day" when Jesus/Yeshua "starts" to reign. That is what makes the DAY (Last Great Day) "GREAT".