Who can say what exactly goes on in the mind of a composer who sets out to depict his innermost religious thoughts and experiences? Is it even possible to put such ineffable ideas into abstract sound?
We may think that this is a fruitless task, but upon reflection, we realize that composers like J.S. Bach, Gabriel Faure, and Igor Stravinsky managed to set down their articles of faith through works that have stood the test of time.
So though it be a daunting task, composers of today are up for it. James MacMillan, in particular, has devoted much of his career to works that work toward define his faith. His large-scale work for chorus and orchestra, Visitatio Sepulchri, is both imbued with his religious philosophy while also being just plain great music.
Gene Pritsker takes a slightly different tack in his suite Varieties of Religious Experience, based on essays by philosopher William James. One movement, The Lesser of the Two, manages to be a profound tract on religious thought without using a single word.