From a friend: Jesus was very clear when he said, ". . . I am the way, the truth, and the life: no man cometh unto the Father, but by me." (John 14:6) There is no reason for telling us to take the gospel into all the world (Mat. 28:18-20), if God has plans to save people without the gospel.
The heathen are commonly spoken of as "the heathen who've never heard," but this is usually a mistake. They might not have heard a clear presentation of the gospel of Christ, but the notion that they are like innocent little children with no concept of right and wrong is false. People everywhere have a conscience that develops and matures with age, and usually before adulthood they have a basic knowledge of good and evil. That's why they have their own laws about theft, murder and other evils, even without the influence of Christian missionaries and Bibles. Paul said this is due to their God-given conscience: "For when the Gentiles, which have not the law, do by nature the things contained in the law, these, having not the law, are a law unto themselves: Which shew the work of the law written in their hearts, their conscience also bearing witness, and their thoughts the mean while accusing or else excusing one another." (Rom. 2:14-15)
This means that the unreached masses have heard more than people realize, because they've heard the still small voice of God speaking through their conscience. They have also heard the voice of nature telling them of God's existence as Creator. Psalms 19 says, "The heavens declare the glory of God; and the firmament sheweth his handywork. Day unto day uttereth speech, and night unto night sheweth knowledge. There is no speech nor language, where their voice is not heard. Their line is gone out through all the earth, and their words to the end of the world . . ." (Psa. 19:1-4)
All of this means that man is without excuse and cannot plead total innocence. Not having heard the gospel doesn't mean that man hasn't heard anything. He's heard enough truth through conscience and nature to develop a response to that truth, and God holds him accountable for it. Paul addresses this in Romans 2:6-11: "Who will render to every man according to his deeds: To them who by patient continuance in well doing seek for glory and honour and immortality, eternal life: But unto them that are contentious, and do not obey the truth, but obey unrighteousness, indignation and wrath, Tribulation and anguish, upon every soul of man that doeth evil, of the Jew first, and also of the Gentile; But glory, honour, and peace, to every man that worketh good, to the Jew first, and also to the Gentile: For there is no respect of persons with God."
As we know, "eternal life" is only available through Jesus Christ (John 10:28-29; 14:6); so Paul is saying that God delivers truth to those who with a good conscience seek for it. Jesus said, "seek, and ye shall find" (Mat. 7:7), and he said, "Blessed are they which do hunger and thirst after righteousness: for they shall be filled." (Mat. 5:6) People everywhere receive at least some light from God (John 1:9), and if they follow that light and seek additional light, then God gives more light and eventually the gospel, if their seeking continues. If not, he eventually sends wrath (Rom. 2:8-9).
The truth of God is a path that everyone chooses or rejects, and it leads to Jesus Christ, even when it doesn't start with Christ. To reject this path is, in essence, to reject the way to Christ, and this is what most people do. Every heart has heard the words "This is the way, walk ye in it" (Isa. 30:21), so everyone is without excuse, because there are no heathen who have never heard.