In the Nicene Creed which Catholics recite the Church is described by four adjectives: One, Holy, Catholic and Apostolic. Though Protestants have been known to take issue with any one of them, the one which seems the easiest to challenge and to misunderstand, especially in the midst of scandal, is that the Church is Holy. If the Church is nothing other than her members, and if her members are on the whole disgracefully sinful and astonishingly unholy (which we are), then what sense is there in calling the Church Holy? First, Catholics do not believe that the Church is nothing other than her members, since the Church is literally identified with Jesus Christ (the Church is the body of Christ, and therefore is Christ in the same way your body is you). However, the Catholic has to make sense of saying that the Church, even as she is now, on earth, filled to the brim with sinners, is essentially holy – what can this mean?
I was thinking today that a good way to explain this might be to adopt Aristotelian language. One believes the Church is holy not because all, most, or any of her members are holy, but because She is able to make people holy. In Aristotelian language we would say that the Church is able to reduce a person from potentially holy to actually holy. But, whatever can reduce a thing from potentiality to actuality must already be in actuality. Thus, the Church must be holy in order to move sinners from being potentially holy to actually holy.
For Aristotle, a thing could only be reduced from potentiality to actuality by another thing which was in that respect in actuality – just as a ball which is potentially moving could only be reduced from that state, to the sate of actually moving, by something else (say, another ball) which was itself actually moving. In this same way the Church must be ‘actually’ holy, and that explains why she takes in such horrific sinners, and produces such astounding saints.