...in using the word "religion" we are already making assumptions which need to be examined. In most human cultures religion is not a separate activity set apart from the rest of life. Neither in practice nor in thought is religion separate from the rest of life. In practice all the life of society is permeated by beliefs which western Europeans would call religious, and in thought what we call religion is a whole worldview, a way of understanding the whole of human experience. The sharp line which modern Western culture has drawn between religious affairs and secular affairs is itself one of the most significant peculiarities of our culture and would be incomprehensible to the vast majority of people who have not been brought into contact with this culture. It follows that in thinking about the implications of the claim that Jesus is God's unique self-revelation for our relation to the world religions, we must take into view more than what we call religion. The contemporary debate about Christianity and the world's religions is generally conducted with the unspoken assumption that "religion" is the primary medium of human contact with the divine. But this assumption has to be questioned. When the New Testament affirms that God has nowhere left himself without witness, there is no suggestion that this witness is necessarily to be found in the sphere of what we call religion. The parables of Jesus are notable for the fact that they speak of secular experiences. When the Fourth Gospel affirms that the light of the Logos who came into the world in Jesus shines on every human being, there is no suggestion that this light is identified with human religion. The text goes on to say that this light shines in the darkness, and the ensuing story constantly suggests that it is religion which is the primary area of darkness, while the common people, unlearned in religious matters, are the ones who respond to the light. And it is significant that Justin Martyr, one of the earliest apologists to use this Johannine teaching in making contact with the unbelieving world, affirms that the true light did indeed shine on the great philosophers like Socrates, but that the contemporary religion was the work of devils. Our thought must therefore be directed not just to the religions so called; we must ask about the relation of the gospel to all who live by other commitments, whether they are called religious or secular.
Lesslie Newbigin. The Gospel in a Pluralist Society, pages 172/3