Progressive revelation is the idea around which Baha'i belief is organized. Religious truth, on this teaching, is not delivered once and for all but unfolds through history: God sends a series of Messengers, or Manifestations, each renewing the same eternal spiritual truths while giving social and legal teachings fitted to the capacity of the age. The line named in Baha'i writings runs through Abraham, Moses, Zoroaster, Krishna, the Buddha, Jesus, Muhammad, and then the Bab and Baha'u'llah. Two consequences follow. First, the religions are not competitors but successive stages of one religion of God. Second, revelation does not stop: Baha'u'llah is held to be the Manifestation for the present cycle, yet a future Manifestation will come when humanity is ready, so no book closes the process for ever.
The teaching directly contradicts the mainstream Muslim doctrine that Muhammad is the Seal of the Prophets, khatam al-nabiyyin, after whom no further law-bearing messenger can come, and this collision is a principal reason Baha'is have been treated as apostates from Islam rather than as a distinct religion by many Muslim authorities, with the Iranian government's persecution of its Baha'i minority, intensified after the 1979 revolution, frequently cited by human rights organizations as a consequence of this doctrinal claim. Historians of religion have also noted the idea's affinity with earlier nineteenth-century currents, such as theosophy's own comparative and evolutionary view of the world's religions, though Baha'i teaching presents progressive revelation as revealed truth rather than a borrowed comparative-religion theory.