Three major issues are especially important here. First is the notion that Christianity completes, supersedes, or abrogates Judaism. Ancient Messianic expectation found its mark in Jesus, Christians believe, thereby rendering Judaism historically irrelevant. Second, Christians believe that in Jesus God has granted the final and definitive revelation. Any post-Christian claims to prophetic authority are therefore unacceptable and not to be believed. Islam is the most obvious example of a claim to prophetic revelation after Jesus, so it is not surprising that the history of Christian-Muslim relations has often been stormy. Third, personal assent to the divine revelation embodied in Jesus is essential to salvation, so that only those who so believe can hope to be rewarded in the hereafter.

For many Christians, it simply does not matter that most human beings through the course of history have never heard of Jesus. In this instance many Christians have in mind not only the 80 percent of humanity that are not Christian, but even some of their fellow Christians whose beliefs they consider flawed or incomplete. Such exclusive views are hardly unique to Christianity. But many Christian groups recently have begun to respond to the reality of the world as it is, with all its religious wealth, by understanding that very diversity as an essential ingredient in the divine plan. From this perspective it is no longer possible to assert simply and categorically that one segment of humanity is assured of salvation while another segment is lost virtually by an accident of birth.