In the Book of Revelation, an angel gives Saint John a literal-sounding tour of the heavenly city with a measuring rod, giving dimensions, numbers of gates, and descriptions of materials (Rev 21:15-17).  But the heavenly city is not a tangible, material place.  It is an icon of the glorified church in which God is seated and the faithful are the "living stones."  This has led some to theorize that since the people are the living stones, then the actual physical building is therefore irrelevant.  Strictly speaking, if "we are church", then the church building, by definition, is not.  What is it then?  The answer, of course, is that the church building is an icon of the full living  church of the Heavenly Jerusalem.   

The metaphorical association of the members of the Church (including the angels, saints, et al.) with the church building takes its cue from scriptural language itself.  Christ, of course, is the stone the builders rejected who has become the cornerstone (Mt 21:42, Mk 12:10, Lk 20:17).  James, Cephas, and John are called "pillars" (Gal 2:9) and Paul speaks of building up the church "like a skilled master builder" who builds the foundation that is Jesus Christ (1 Cor 3:10-11).  In Ephesians, Paul explicitly compares the people of the church to an edifice, calling Christians "citizens with the saints and members of the household of God, built upon the foundation of the apostles and prophets, with Christ Jesus as the cornerstone" (Eph 2:19-22).  Similarly, Peter calls Christians "living stones" built into a "spiritual edifice" (1 Pt 2:4), a phrase used by the American bishops in naming their own document on church architecture, Built of Living Stones.  So the church building, then, is an icon of the Heavenly Jerusalem, which itself is made up of the Trinity and celestial beings surrounded by living stones of the saints.  Making this invisible spiritual reality appear to us in material form is the very essence of the sacramentality of a church building.

Sacraments are never exact images of the realities they signify, so churches we build will never literally "look like" heaven.  But, by definition, sacraments use conventional forms that humans understand.  So, what do we make our sacramental heavenly city "look like"?  The Book of Revelation tells us its length, width, and height are equal, making it roughly cubic in shape.  The city has twelve foundations, each with a name of one of the apostles upon it.  Its twelve gates are like pearls, and the walls are made of precious gems including jasper, sapphire, onyx, and topaz.  Additionally, the city is described as "pure gold, clear as glass" and filled with radiant light of the glory of God (Rev 21:15-27).

One need think of any well-ornamented church from the early Christian period through the twentieth century to see an understanding of church building as icon of the heavenly Jerusalem.  Glimmering gem-like mosaics combine with rich materials and images of Christ and the saints to fill these churches with iconic representations of the heavenly realm.  Similarly, the Gothic cathedral, with its great expanses of glowing stained glass and colorfully painted and gilded interiors evoke the heavenly city, as did the buildings of hte Renaissance and high baroque, with angels and saints swirling around interiors made of precious marbles and gold.  Eastern-rite Catholics and Orthodox have maintained this sense of the sacramental nature of church architecture, even in contemporary churches, often basing their buildings on the proportions given by the angel and covering the interiors with icons over gold leaf.

*Excerpt from "Built Form of Theology" by Denis McNamara, appearing in Volume 12 of "Sacred Architecture" (www.sacredarchitecture.org)