What happens to people who do not believe in Christianity due to a lack of exposure? (For example, people who may live remotely, or people who are of a different religion and have never been exposed to Christianity.)
God reveals his existence by means of what we call the “natural knowledge of God.” Through creation (Psalm 19:1-4) and conscience (Romans 2:14-15), God makes it known that he exists. While people cannot bring themselves to saving faith, God’s purpose with this “natural knowledge” is that people would “seek him and perhaps reach out for him and find him, though he is not far from any one of us” (Acts 17:27).
Apart from the Bible, people know that there is a God, they know the basics of the Ten Commandments and they have a conscience that reacts to their thoughts and words and actions. It is only in the Bible though where people find the answer to the question: “What must I do to be saved?” (Acts 16:30) There is salvation only in Jesus Christ (Acts 4:12). What God reveals in the Bible is that faith in Jesus is essential for salvation (Mark 16:16). God also reveals that he brings people to saving faith in Jesus through his gospel in word and sacrament (Romans 10:14-17).
So, what about people who have not “been exposed to Christianity?” Through technological advances, the message of the Bible is reaching more and more parts of our world. Yet, there are people who have never heard of the gospel of Jesus Christ; some of those people may live closer to us than we think. What about their eternal fate if their lives on earth come to an end with an ignorance of the gospel?
Is God to blame for their situation? Not at all. We need to put the blame where it belongs: on people and not on God. There were times when the entire human race knew the gospel. Back in the Garden of Eden and after the Flood in Noah’s day, every person on the face of the earth knew the gospel. When we consider a question like yours, we have to ask: “When and where did communication break down? Where did communication of the gospel break down? Who dropped the ball in teaching the gospel to the next generation?” It does not take much for communication—and gospel communication—to break down, and the results are tragic.
So what we are left with is what God says in his word about the necessity of faith and the necessity to spread the gospel so the Holy Spirit can work through it and bring others to saving faith in Jesus. Your question is one that emphasizes how important it is to do what Jesus said two millennia ago: “Go into all the world and preach the gospel to all creation” (Mark 16:15).