Baha’u’llah validates an Islamic tradition which mentions “four signs from four Prophets” to be appeared in the Qá’im (the Báb)

In the “Bihár” it is recorded: “In our Qá’im there shall be four signs from four Prophets, Moses, Jesus, Joseph, and Muhammad. The sign from Moses, is fear and expectation; from Jesus, that which was spoken of Him; from Joseph, imprisonment and dissimulation; from Muhammad, the revelation of a Book similar to the Qur’án.” 

- Baha’u’llah  (‘The Kitab-i-Iqan’)