The entirety of Schoenberg’s “Moses und Aron” is on YouTube (just the music, not a staged version of the opera):
So too is his Jacobsleiter (Jacob’s Ladder):
Both are fascinating works in terms of both their relationship to Schoenberg’s developing artistic vision (often referred to, despite Schoenberg’s objections, as “atonality”) and his own religious views. I can’t help but think that Schoenberg knew and intended as symbolic not only the opera Moses und Aron (even the spelling of Aaron’s name was intentional and relates to numerology), but the leaving of it unfinished with the third and final act never scored, since the whole emphasis in the piece is the contrast between pure unutterable ideal, and image/idol/performance, and as it stands the piece delivers opposite messages about precisely this point depending on whether you read the score or attend a performance of the opera. This tension is in fact at the heart of all music, and all religion.