Can the heathen be saved having never heard the gospel? "Faith comes by hearing, and hearing by the Word of God" (Romans 10:17). "How will they call on Him in whom they have not believed" (Romans 10:14).
Do unreached peoples have a chance to believe? "Their line has gone out through all the earth, and their utterances to the end of the world" (Isaiah 19:4). "Who has believed our message?" (Isa 19:4) since "surely they have never heard, have they?" (Romans 10:17).
Does hearing the gospel save a person? The gospel "is the power of God for salvation to every one who believes" (Romans 1:16). It is "with the heart man believes" (Romans 10:10) and not just by hearing.
Does it also take a positive mental attitude to be saved? "If any man is willing . . . he shall know of the teaching" (John 7:17). Scriptures "have been written that you may believe that Jesus is the Christ" (Jn 20:31).
Is scripture necessary for salvation? "The message of truth [is] the gospel of your salvation" (Eph 1:13) since "He brought us forth by the word of truth" (James 1:18). God "desires all men to be saved and to come to the knowledge of the truth" (1 Tim 2:4).