Nice essay (in PDF format) from Brother John of the Taiz?© Community.
How can we define the distinctive character of the Christian faith? Does it lie in baptism, in the creed we sometimes recite, or in particular moral values? Does following certain practices, such as going to church on Sunday morning, make one a Christian? Does it mean having certain specific ideas about the world or human life? This question is obviously of the utmost importance, both for those who want to profess this faith and for those who intend to reject it. Otherwise, it may even happen that we reject it for the wrong reasons. As for those who accept it, it would be a shame if they were to discover that, neglecting what is essential, they were focusing on elements that are only secondary. In so doing, they do not help others to discover what is characteristic about Christianity. In the following pages, then, we will attempt to answer this crucial question in successive stages.