Who Can Be Saved?
Someone asked, “Will the heathen who have never heard the Gospel be saved?” It is more a question with me whether we — who have the Gospel and fail to give it to those who have not — can be saved. — Charles Spurgeon
See Ezekiel 33; Acts 18:5,6; Mark 16:15
Please also see:
this report of a conversation between a Christian and a muslim enquirer.