Seriously? Forty posts and no one has stated the obvious?
If one doesn't "hear" (or read) the gospel, how in the world will they have the basis of knowledge to believe for salvation?
They won't:
Rom 10:13 For "everyone who calls on the name of the Lord will be saved."
Rom 10:14 How then will they call on him in whom they have not believed? And how are they to believe in him of whom they have never heard? And how are they to hear without someone preaching?
Rom 10:15 And how are they to preach unless they are sent? As it is written, "How beautiful are the feet of those who preach the good news!"
Rom 10:16 But they have not all obeyed the gospel. For Isaiah says, "Lord, who has believed what he has heard from us?"
Rom 10:17 So faith comes from hearing, and hearing through the word of Christ.