The pulpit or mimbar منبر, used for the recital of the kutbah on Fridays in the chief mosque is usually a wooden structure of three steps and movable, but in the large mosques of Turkey and Egypt it is a fixture of brick or stone.
It is related that the Prophet, when addressing the people, stood on the uttermost step, Abu Bakr on the second, and ‘Umar on
the third or lowest. ‘Usman being the most humble of men, would gladly have descended lower, but this being impossible, he fixed upon the second step, from which it is now usual to recite tho khutbah on Fridays and on the two great festivals [MOSQUE, MIMBAR.]
Based on Hughes, Dictionary of Islam