You also, as living stones, are built up as a spiritual house, to be a holy priesthood, to offer up spiritual sacrifices, acceptable to God through Jesus Christ.

 The point is clear. So long as a brick lies by itself it is useless; it becomes of use only when it is incorporated into a building. So it is with the individual Christian. To realize his destiny he must not remain alone, but must be built into the fabric of the Church. 