The significance of the number nine...

"First, regarding the significance of the number nine: Its importance as a symbol used so often in various connections by the believers lies in three facts: first, it symbolizes the nine great world religions of which we have any definite historical knowledge, including the Babi and Bahá'í Revelations; second, it represents the number of perfection, being the highest single number; third, it is the numerical value of the word 'Baha'."

(From a letter written on behalf of Shoghi Effendi to an individual believer, July 9, 1939)