Note: Preterist amillennialists proclaim that the gospel was preached throughout the earth during the apostolic age.
Matthew then reports more of the discourse: "And this gospel of the kingdom will be preached in all the world as a witness to all the nations, and then the end will come" (Matt. 24:14). Jesus cites another phenomenon that must take place before "the end" comes: The gospel will be preached in all the world. This "sign" is widely regarded today as being unfulfilled, as there remain remote tribes and peoples who have not yet heard the gospel.
Russell argues, however, that this precursor to the end was already accomplished in apostolic times: "One other 'sign' was to precede and usher in the consummation," writes Russell. "'The gospel of the kingdom shall be preached in all the world (oikoumene) for a witness unto all nations: and then shall the end come.' We have already adverted (or alluded) to the fulfillment of this prediction within the apostolic age. We have the authority of St. Paul for such a universal diffusion of the gospel in his days as to verify the saying of our Lord. (See Col. 1:6, 23.) But for this explicit testimony from an apostle it would have been impossible to persuade some expositors that our Lord's words had been in any sense fulfilled previous to the destruction of Jerusalem." (J. Stuart Russell, The Parousia, pages 70-71, 1878, reprinted 1983)
The passage in question reads as follows: "(The gospel) has come to you, as it has also in all the world, and is bringing forth fruit, as it is also among you since the day you heard and knew the grace of God in truth....if indeed you continue in the faith, grounded and steadfast, and are not moved away from the hope of the gospel which you heard, which was preached to every creature under heaven, of which I, Paul, became a minister" (Col. 1:6, 23).
If the amillennialists are correct, then the gospel was preached in the Americas during the apostolic age. The Mormons (the Church of Jesus Christ of Latter-day Saints) would be in full agreement with this interpretation since their Book of Mormon teaches that Jesus Christ proclaimed the gospel in the New World after His resurrection. Orthodox Christians should be wary when their eschatological interpretations agree with cults. Accordingly, Colossians 1:23 must be interpreted as being the "Roman" world and not used to define the fulfillment of Matthew 24:14. Scriptural support is found in Luke 2:1 which reads: "And it came to pass in those days that a decree went out from Caesar Augustus that all the world should be registered." Did any civilization outside the "Roman" world such as China or the Americas obey Caesar? Of course not!
Some amillennialists try to explain that "the world" in Matthew 24:14 refers to the land of Israel or the "Roman" world. This interpretation would be inconsistent with other usage's of world or earth in Matthew chapter 24. Moreover, Jesus uses the illustration of "the days of Noah" in verse 37 and Noah never lived in the land of Israel or the "Roman" world.
The amillennial skeptics will probably ask how will the gospel be preached throughout planet earth if not by the church. The gospel will ultimately be preached throughout the world by a angel as described in Revelation 14:6-7. Then I saw another angel flying in the midst of heaven, having the everlasting gospel to preach to those who dwell on the earth; to every nation, tribe, tongue, and people; saying with a loud voice, "Fear God and give glory to Him, for the hour of His judgment has come; and worship Him who made heaven and earth, the sea and springs of water." Thus, Scripture is eventually fulfilled and the end of the world occurs.