It's the full moon of the Feast of Tabernacles, (or booths) one of the Older Testament's pilgrim feasts. It's also the fall harvest festival where people from all nations gathered to worship the one true God.

And they found written in the law which the LORD had commanded by Moses, that the children of Israel should dwell in booths in the feast of the seventh month: Neh 8:4

Then it will come about that any who are left of all the nations that went against Jerusalem will go up from year to year to worship the King, the LORD of hosts, and to celebrate the Feast of Booths.

And it shall come to pass, that every one that is left of all the nations which came against Jerusalem shall even go up from year to year to worship the King, the LORD of hosts, and to keep the feast of tabernacles. Zech. 14:16

Originally, the Greek term translated Jew referred to the Judeans, and in particular to the leadership. Just as in our day, everyday people were divided about Jesus, but the leadership was in large part opposed to him:

Jhn 7:2

Now the feast of the Jews, the Feast of Booths, was near. So the Jews were seeking Him at the feast and were saying, “Where is He?” There was much grumbling among the crowds concerning Him; some were saying, “He is a good man”; others were saying, “No, on the contrary, He leads the people astray.”

(NASB 95)

Here is the Link from Blue Letter Bible to the KJV for this verse, and the verse from Zechariah, which calls the Feast - The Feast of Tabernacles, which it is called today.

And it shall come to pass, that every one that is left of all the nations which came against Jerusalem shall even go up from year to year to worship the King, the LORD of hosts, and to keep the feast of tabernacles. Zech. 14:16

https://www.blueletterbible.org/kjv/jhn/7/38/s_1004038 https://www.blueletterbible.org/kjv/zec/14/1/s_925001