Isaiah 66:20
And they shall bring all your brethren for an offering unto the LORD out of all nations upon horses, and in chariots, and in litters, and upon mules, and upon swift beasts, to my holy mountain Jerusalem, saith the LORD, as the children of Israel bring an offering in a clean vessel into the house of the LORD.
This promise finds literal fulfillment in the gospel age, when bearers of the glad tidings of salvation go to the ends of the earth to every kindred and people. The Lord sends His witnesses to the nations — to Tarshish, and Pul, and Lud, to Tubal and Javan, to the isles afar off — to declare His glory among the Gentiles. The result is that brethren are brought for an offering unto the Lord out of all nations to His holy mountain Jerusalem, which is the gospel church. Those thus gathered from the nations are also taken for priests and for Levites, showing that salvation is carried to every nation and kindred and tongue and people and that the church is enlarged to inherit the Gentiles.