April 15

...concerning those passages in "The Hidden Words" in which Bahá'u'lláh refers to man as "Son of Spirit", "Son of existence", "Son of humanity", etc., the word "son" used in this connection is a kind of collective noun meaning mankind and has, therefore, no connotation of any sex differentiation between man and woman whatever. 
- Shoghi Effendi  (From a letter dated 19 January 1935 written on behalf of Shoghi Effendi to an individual believer; compilation ‘Hidden Words: References of ‘Abdu’l-Bahá and Shoghi Effendi’, prepared by the Research Department of the Universal House of Justice)