If Jesus is so great and the path to salvation, what about those who have never heard or him? Are they cut out because of an accident of history i.e. they were born before his coming or lived in a place where his salvation message was unknown? That hardly sounds fair does it? Some hardline Christians take this view; however I disagree.
For me the bible, while not fully answering the question, gives us some good pointers in terms of answering this question.
The main lead is the way in which the New Testament refers to a number of people are have been saved and have gone to live with God for eternity, but they never heard about Jesus! People like Abraham (Rom 4) and a whole long list of people in Hebrews 11. It is worth examining why they were saved.
We can say for certain that they were not saved because of a perfect life; that is ruled out in the NT totally. In fact, examination shows that none of these people lived a perfect life. Hence, they were not saved because of the things they did per se. They were flawed people who made mistakes. Some like Samson even rejected God for great periods of their life (see Jdg 13-16).
Rather, they were saved because of their faithful relationship with God as they knew him (Rom 4:3; Heb 11:1, 39-40). These people were all saved because they walked through to their death in a living trusting relationship with God in terms of the way he had been revealed to them.
Abraham for example lived for many years trusting God and doing what he said. He made mistakes but hung in there. He knew God as ‘El', the God of his ancestors who he worshiped at shrines and as a nomad. He knew nothing about him as Yahweh or as the God of Israel, for Israel did not exist at this point. He knew nothing about Jesus or crucifixion or resurrection. Yet he was saved.
Similarly Moses knew God as Yahweh, who he met supernaturally in a burning bush, who he met on a mountain, who he disobeyed on occasion. Yet he was saved on the basis of his lifelong faithful relationship.
Hence we can conclude that in other cultures where Christ has not been preached there are others like Abraham and Moses who know God and walk in faithful relationship with him.
However, they were not saved by their religions! Rather they were saved by a living faith in God. Consequently, one can be saved necessarily through Islam, through Hinduism, through Judiasm or Buddhism. These are all flawed and inaccurate expressions of faith. However, where Christ has not yet been made known, or where he has been made known inaccurately, it is possible that people within these religious systems may be saved through their faithful relationship with the God they meet through creation and personal revelation.
Neither are these people saved through their view of God, they were saved retroactively by Jesus. This means that while they did not believe in Jesus in the contemporary Christian sense, they are still saved by his death and resurrection because of their faithful relationship with God.
The cross works across all of time for those who had a faith-relationship with God until their death.
The NT makes clear that is those who endure in their faith to the end that are saved. Hence it is not enough to say yes to God, get baptised and then expect to be saved. One must remain in that faithful relationship to the point of death to receive salvation (see Mt 20:1-16; 21:28-32; 24:13; 25:1-13; 1 Cor 15:2; Heb 6:1-8; Rev 2:26 etc.)
I conclude that those who have not heard about Christ still have/had opportunity to be saved. However, they are not saved through any religious system but through an active living faith in God as they know him through creation, personal experience and history. Once a person has heard the message concerning Christ clearly explained then it is on the basis of their faith in Christ as heard in the message that they are saved.