As with so many other religions, Muad'Dib's Golden Elixir of Life degenerated into external wizardry. Its mystical signs became mere symbols for deeper psychological processes, and those processes, of course, ran wild. What they needed was a living god, and they didn't have one, a situation which Muad'Dib's son has corrected.
Attributed to: Lu Tung-pin
From Chapter 64 of Children of Dune by Herbert, Frank