Human beings as a lot are incurably religious. The problem is that since these 1 same human beings are also infected by sin, they tend not to desire to honor and glorify the true God, who is righteous and holy. Rather, they tend to make gods for themselves that are pleasing to them or that satisfy some sense of what they think a god ought to be. As John Calvin said, the human mind is a factory for idols. Such gods, concocted by the rationale of humans apart from special revelation, are invariably out of touch with the truth (Rm 1:18-32).
What hope is there for those who do not live in predominantly Christian parts of the world? Historically, Christians have argued that their hope lies in the mission impulse of the Christian church. From the earliest days of Christianity, Jewish believers began to spread the message to the Gentile world (Ac 10-11). Christians such as the Apostle Paul made it clear that it was not good enough even to be a Jew, since the hope for salvation rests in affirming Jesus as Messiah (Php 3:7-11). In the early centuries of the faith, Christians spread the message to Africa, northern Europe, the British Isles, and the Asian subcontinent, all because they believed this message was the hope of salvation for the world.
It is obvious to anyone that vast numbers of people in the world today either have never heard the gospel or have heard it in only a cursory manner. What hope do such people have? The Bible makes it clear that there is no salvation in any name other than that of Christ (Jn 14:6; Ac 4:12). That means that one must believe specifically in Jesus in order to be saved (Rm 10:9-14). Does this mean that most people ever born will spend eternity in hell? If so, is that a problem for the Christian faith?
A couple of proposals have been offered to respond to this difficulty. Some have suggested that God will evaluate all people according to the "light they have." That is, if someone is a Hindu or a Muslim or an ancient Aztec, God will judge that person only according to his response to the religious information he has at hand. The problem is that the Bible regularly condemns idolatry. Scripture even indicates that idolaters know intuitively that there is something wrong with their idolatry (Rm 1:19-20). The other problem is that many actions of religious people are terrible. Hindu Kali worshipers murdered travelers, and Aztecs sacrificed young women to their god. Another proposal is that God will simply save all persons by His power. The difficulty here is that it ignores human free will as well as the fact that the Bible indicates that some will eventually go to everlasting punishment (Mt 25:46).
Christians must hold that faith in Christ, and only faith in Christ, is the avenue to salvation. But having said that, God will judge those who have heard the truth and yet have rejected it more severely that those who have never heard (Lk 10:14). There is also the hope that in the future the church's message of salvation will cover the entire earth.
(For another perspective, see “What About Those Who Have Never Heard About Christ? by William Lane Craig”)
Extracted from the Apologetics Study Bible.