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.
Yes, I saw that, but Rev 19:21 shows that the remnant not slain at first, would also be slain.
And the remnant were slain with the sword of him that sat upon the horse, which sword proceeded out of his mouth: and all the fowls were filled with their flesh.
And so it could be read slightly different: Everyone that is left, of all the nations that came against Jerusalem, shall even go up...
Out of all those nations that did go to war, there is always them that are left in the nations.
It will not be a gathering of all them in all nations at one place for war.
But, either way, it proves the point that there will be them left of all nations, that will go up from year to year during the Lord's reign on earth.