Zechariah 14:16 Then everyone who survives of all the nations that have come against Jerusalem shall go up year after year to worship the King, the LORD of hosts, and to keep the Feast of Booths. (ESV)
Well, its pretty obvious. We see this come up again and again in the Old Testament (OT). Its 
about mission! How is it that we keep reducing the OT to Levitical laws and moral examples. The Abrahamic covenant is to bless all the nations of the earth through Abraham’s descendants. And we see it fulfilled here in this apocalyptic consummation which concludes Zechariah’s prophecies.
Living waters will flow out of Jerusalem (v. 8). All the nations come and join God’s people in the worship of Yahweh. Even the bells on every horse shall be consecrated (v. 20). And every common pot shall be called holy and used for worship (v. 21). The redemption is complete and comprehensive.
Help me Lord to see my role in worldwide mission clearly God. Empower me and enable me to point others to the King. Jesus be glorified. Be exalted in our worship. Draw the nations by Your power, Your love, Your Spirit. Come Holy Spirit.
In Jesus’ name – Amen,
Son