Manichaeism divided its entire community into two ranks, and the gap between them was not a matter of degree but of an almost total difference in daily life. The Elect kept a discipline built around what Manichaean texts call the Three Seals: the seal of the mouth, governing diet, blasphemy and impure speech; the seal of the hand, forbidding harm to any living thing, including plants, which Manichaean cosmology held to contain trapped particles of divine light; and the seal of the breast, requiring celibacy and general sexual abstinence. Taken together these rules meant an Elect member could not farm, cook, slaughter an animal, harvest a plant, marry, or generally hold property, restrictions severe enough that the rank was never going to be a mass status; the Elect were always a small, celibate, wandering or monastically settled core surrounded by a much larger lay population.
The doctrinal reasoning behind the diet is central rather than incidental. Manichaean cosmology held that particles of divine light were scattered throughout the material world, trapped in plants above all, and that eating particular light-rich foods, principally fruit, allowed an Elect member's digestion to liberate that trapped light and send it on its way back toward its divine source, a process sometimes described in Manichaean texts in terms close to a bodily ritual rather than mere nutrition. Because only the Elect could perform this liberating digestion correctly, and because they were forbidden to grow or prepare their own food without risking harm to the light trapped in it, the whole system depended structurally on a second class willing to do that labor on the Elect's behalf.