B. Hodge, Biblical Authority Ministries, July 1, 2020
Many theologians today claim that the Gospel must first be preached in the whole world before the Christ will return and this is to be fulfilled in the future. Contextually though, this is actually speaking of the gospel being preached in every nation prior to the destruction of the Temple. But did that happen?
At the first preaching of the gospel after the resurrection of Christ, there were people representing every nation under heaven (Acts 2:5). This should be enough to settle the issue. But further, these people preached the gospel back in their homelands. Many Christians were scattered among the nations due to Jewish persecution (Acts 8:1-8), taking the gospel with them where they went.
The apostles, not just Peter and Paul, took the message to many places like Philip to the South even converting a leading Cushite (Ethiopian) who surely took the gospel back to Africa (Acts 8:26-40). A suggested study of where the apostles took the gospel is an interesting endeavor that is encouraged but not for this study.
Acts 10-11 show the speed at which the gospel was spreading in the apostolic age. There were already Christians in Rome awaiting Paul when he arrived (Acts 28:11-15). There were even Christians in Nero Caesar’s own household (Philippians 4:22). Without a doubt, Paul could rightly state that the message of the gospel had been preached to all the nations by the time of his letters to Colossi and Rome (Colossians 1:6, 1:23; Romans 1:8; Romans 16:26).
Read Revelation 20:11-15 twice.
 With caveats that I don’t agree with everything published in this book, I tentatively suggest: William McBirnie, The Search for the Twelve Apostles, Tyndale House Publishers, Inc., Carol Stream, IL, 1973.