The present essay deals with the paradoxical loss of relevance of a Christian Church, which is making more efforts than ever in order to be relevant. We are arguing that what many Christians understand as ‘relevant’ is actually a diluting of the message of the Cross and, hence, a crass ‘irrelevance’ by consequence, since only the pure Good News can ever be relevant. Only the ‘shocking’ message of the Cross and the ‘shocking’ righteous life of the followers of Christ can be relevant. To be relevant implies maintaining the distinction between the sacred space and the profane space, and not the diluting of our teaching and behaviour with the habits and ideas of the culture at large. Founding a definition of relevance on an essential passage in the Sermon on the Mount, we will show that to be relevant means to live your Christian life selfsacrificially, ‘burning away’ visibly, and elevating God and yourself above the surrounding culture, hence evading the two extremes of secularization (which entails the watering down of doctrine) and of ghettoization (which entails a sectarian isolation, a perennial lack of visibility).