A Study of the prophecy of the Zechariah 14:16-19 and going up to the "New Jerusalem" to Keep the Feast of Tabernacles. The time of the fulfillment of this prophecy is "in that day" i.e. the eschatology day of the Lord when the kingdom is fulfilled in 70AD (Lk. 21:31-32; Heb. 12:18-23).
The temple is no longer geo-centric, i.e. located in Jerusalem in Mt. Zion. It is located in God and Christ and is in fact God and Christ. The temple is now spiritual and the Feast of Tabernacles is kept by worshiping "in the Father and the Son".
Those converted to Christ from Egypt enter the kingdom and keep the Feast of Tabernacles, worshiping the King. The Canaanite has also been converted to Christ. So the new Israel is comprised of the remnant from Israel, including those who were left of the nations any where in the world where they are found.
The old physical Jerusalem is no longer the place of God's worship and Presence and the destruction of the temple in 70AD is the final testimony of that fact.
Heb. 12:23, shows that those who come into the kingdom come to the Festal Gathering or Feast of Tabernacles.