For out of Jerusalem shall go forth a remnant, and they that escape out of mount Zion: the zeal of the LORD of hosts shall do this. Out of Jerusalem shall go forth a remnant - The Jews shall be so multiplied as not only to fill Jerusalem, but all the adjacent country.
And they that escape out of Mount Zion - Some think that this refers to the going forth of the apostles to the Gentile world, and converting the nations by the preaching of the Gospel.