May 1

…letters written on behalf of Shoghi Effendi "related strictly to the Cause and interpretation of the teachings" constitute authoritative Bahá'í text, while any personal advice which they may contain is not binding. The Guardian's statement that he reviewed every letter written on his behalf without exception makes it clear that the authority of the letters was independent of whatever personal "sufferings" might have been caused by certain secretaries, and that there was no "delegation" whatsoever of his interpretative authority, but merely a use of secretarial assistance for his huge burden of correspondence. 
(Memorandum from the Research Department of the Universal House of Justice, dated 13 October 1994, attached to a letter dated 22, October 1996 written on behalf of the Universal House of Justice to an individual believer)