I believe that Evangelicals often unwittingly contribute to the politically correct view that Christ is only one way among many.
Let me state first what is biblically and historically true: Christians who have been born again through faith in Christ alone are saved in the NT sense of the term (Luke 1:68-79; 2:30-32, etc.). This, however, is not and cannot be eternally true. After all, the Bible makes it pellucidly clear that the OT saints, including John the Baptist, though justified by faith, were not born again and hence were not the recipients of NT salvation (cf. Mt. 3:14; Heb. 11:39f.). It was only after the Spirit had been poured at Jesus’ exaltation to the Father’s right hand (cf. John 7:39) that the OT promises (Dt. 29:4; 30:6, etc.) were fulfilled (Acts 2:14ff.). As Paul indicates in Galatians 3:2,5, the Spirit who regenerates is received only by specific faith in Christ and not by keeping the law (cf. Acts 2:38; Rom. 8:9; Eph. 1:13). Even for Abraham the blessing was only a promise (Gal. 3:14,18, cf. John 8:56; Heb. 11:13). Just as he personally never inherited the Promised Land during his earthly existence (cf. Acts 7:5), so he never experienced NT salvation (though note Hebrews 11:39f.).
The problem is that Christians, in the grip of a false covenant theology of one kind or another, have simply assumed that regeneration, rather than faith which is relative, is first in the order of salvation. This inevitably means that all who are not born again are damned – an inference which simply cannot be sustained, first, because it means that the number of those who are ultimately saved is lamentably small, second, that sin has triumphed over grace and, third, unregenerate believers like Abraham before Christ were also damned despite clear teaching to the contrary (e.g. Mt. 8:11). Even that much misunderstood passage, Romans 5:12-21, tells a different tale and insists that “where sin increased, grace abounded all the more”. To confine this to quality as opposed to quantity is to attribute a mere Pyrrhic victory to Christ. For not only does my Bible teach me that God so loved the world but also that men and women (and surely children of understanding, if not infants!) from “every nation, from all tribes and peoples and languages” (ESV) will cry “Salvation belongs to our God who sits on the throne and to the Lamb!” (Rev. 7:9) in contrast to those who worship the beast (Rev. 13:7f.). In other words, as Jesus intimated in the judgement scene in Matthew 25:31ff., even many who never knew him will be sheep (see verses 37-39) and not goats (see verse 44). Good and evil pervade Scripture from beginning to end (cf. e.g. the intercession of Abraham, Gen. 18:25ff.).
Clearly it is time that we abandoned the Augustinian notion that all people who do not know Christ through the Christian gospel are an undifferentiated mass of damned humanity (massa damnata or massa perditionis, cf. Westminster Larger Catechism, 60). Until we do, we do violence among other things to the sovereignty of God and his saving grace, to biblical covenant theology, to the pre- as well as the post-incarnate activity of Jesus and to the effectiveness of the plan of salvation throughout history (cf. Heb. 11 where not a single Christian figures until the ‘us’ of v.40!).
Of course, some will complain that this cuts the nerve of evangelism. Such a view reflects a misunderstanding of the issue, though I admit that it needs spelling out.
I will conclude with the rather paradoxical comment that while Christianity is rigorously exclusive (Christ only), it is also gloriously inclusive in that it embraces the world. While universalism is out of the question, nonetheless just as righteousness and peace kiss each other so in a real sense do creation and redemption.