As the ark of salvation, the Church should literally and theologically convey a sense of safety—both spiritual and physical. The following quotes come from Michael S. Rose.
There are several ways a church can assert its permanence. First, and most obvious, is by its durability. The church, a building that will serve generation after generation, transcending time and culture, must be constructed of durable materials. Mere sticks and stones, shingles and tar won’t do. Typically, one or another type of masonry construction is used, employing the finest materials available.
Related to durability is massing: the church must be of significant mass, built with solid foundations, thick walls, and allowing for generous interior spaces. This massing is another aspect of the architectural language of churches. It’s integral to be verticality (the massing of volumes upward creates verticality) and iconography (the massing of the church helps it convey its iconic meaning, i.e., its massing can make a church look like a church and function like a church).
Architects of future generations need to comprehend the language of church architecture in order to build permanent sacred edifices for their own times and future centuries. No successful church architect can be—or even pretend to be—ignorant of the Church’s historical patrimony. Continuity demands that a successful church design can’t spring from the whims of man or the fashion of the day. The architect who breaks completely with architectural tradition robs his church of the quality of permanence that is essential to any successful church design.