My brother and I disagree about Matthew 24:14. I used it in relation to where Paul said the Gospel has been preached in all the world. His response was that was saying Jesus' death had been proclaimed to all the earth but not preached. I understand his point of view because it says every creature (which is impossible), but it is also written with us in mind. That is why the Gentiles have no excuse. And didn't Paul want to go where the Gospel had not been preached? I'm not sure about the time frame of the books but wasn't it after his other statement?
"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" (Matthew 24:14).
"And He said to them, "Go into all the world and preach the gospel to every creature." ... And they went out and preached everywhere, the Lord working with them and confirming the word through the accompanying signs. Amen" (Mark 16:15, 20).
"Since we heard of your faith in Christ Jesus and of your love for all the saints; because of the hope which is laid up for you in heaven, of which you heard before in the word of the truth of the gospel, which 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" (Colossians 1:4-6).
"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" (Colossians 1:23).
"But I say, have they not heard? Yes indeed: "Their sound has gone out to all the earth, And their words to the ends of the world"" (Romans 10:18).
Whether your brother likes it or not:
- Jesus stated that the gospel would be preached in all the world.
- He commanded the apostles to preach the gospel in all the world.
- The New Testament said it had been accomplished.
Paul did state that he preferred working in places where others had not yet worked. "For I will not dare to speak of any of those things which Christ has not accomplished through me, in word and deed, to make the Gentiles obedient -- in mighty signs and wonders, by the power of the Spirit of God, so that from Jerusalem and round about to Illyricum I have fully preached the gospel of Christ. And so I have made it my aim to preach the gospel, not where Christ was named, lest I should build on another man's foundation, but as it is written: 'To whom He was not announced, they shall see; And those who have not heard shall understand.'" (Romans 15:18-21). He goes on to mention his desire to go to Spain, probably for this very reason (Romans 15:23-24). But it was in this same letter that Paul had earlier stated that word of the Gospel had gone through the whole world. Paul mentions this same policy in another letter, "For we are not overextending ourselves (as though our authority did not extend to you), for it was to you that we came with the gospel of Christ; not boasting of things beyond measure, that is, in other men's labors, but having hope, that as your faith is increased, we shall be greatly enlarged by you in our sphere" (II Corinthians 10:14-15).
Paul selected regions to teach where other apostles had not yet gone. He was planning to go to Rome, which was the occasion of his letter to them in part to establish them because at the time no apostle had been there yet. "For God is my witness, whom I serve with my spirit in the gospel of His Son, that without ceasing I make mention of you always in my prayers, making request if, by some means, now at last I may find a way in the will of God to come to you. For I long to see you, that I may impart to you some spiritual gift, so that you may be established -- that is, that I may be encouraged together with you by the mutual faith both of you and me" (Romans 1:9-12). It is because Paul mentions there is a lack of spiritual gifts among the Romans and we know the gifts of the Spirit were distributed by the laying on of the apostles' hands (Acts 8:14-17) that we conclude no apostle had yet visited Rome and Paul wanted to be the first. But this doesn't mean the Gospel wasn't already known in Rome. Quite the opposite actually. A well-known church already existed in Rome. "First, I thank my God through Jesus Christ for you all, that your faith is spoken of throughout the whole world" (Romans 1:8).
People tend to forget about the power of geometric progressions. It wasn't just twelve men preaching the gospel. These twelve on the day of Pentecost taught a large crowd, of whom 3,000 responded (Acts 2:41). More were soon added (Acts 4:4). And when persecution hit the church, "Therefore those who were scattered went everywhere preaching the word" (Acts 8:4). Those they taught would also take up the task. There would have been hundreds of thousands of people who seriously took it as their duty to teach others the gospel. No wonder the world heard the gospel in such short order.
You probably heard the idea that there are six degrees of separation between every person in the world. It comes from the fact that each person has a number of people they know. Those people, in turn, know a number of people. As a result, you can give a person a letter to be delivered to any person in the world, they can pass that letter on through friends, and it will arrive at the determined person passing through, on average, only six hands.
Let's say the average person knows a hundred people well. Then if you include the person and all his friends, they know 10,000 people. If you include the original person, his friends, and their friends, then they know a million people. If you include all million people, they would know a hundred million people. Add in the fifth set of people and you now cover 10 billion people -- more than the world's current population. Of course, there is going to be an overlap of common friends, but I think you see that it doesn't take long to find connections between people. (That is why pyramid sales schemes are illegal, there aren't enough people in the world to allow to sustain recruitment very long.) The world's population was a lot less in the days of the early church. So yes, it is possible for every person in the world to have heard of the gospel message. It doesn't mean they all responded to the message, but it also doesn't mean it was unknown.