....
However, quite apart from his function as a member and sacred head for life of the Universal House of Justice, the Guardian, functioning within his own sphere, had the right and duty "to define the sphere of the legislative action" of the Universal House of Justice. In other words, he had the authority to state whether a matter was or was not already covered by the Sacred Texts and therefore whether it was within the authority of the Universal House of Justice to legislate upon it.... The question therefore arises: In the absence of the Guardian, is the Universal House of Justice in danger of straying outside its proper sphere and thus falling into error? Here we must remember three things: First, Shoghi Effendi, during the thirty-six years of his Guardianship, has already made innumerable such definitions, supplementing those made by 'Abdu'l-Bahá and by Bahá'u'lláh Himself. As already announced to the friends, a careful study of the Writings and interpretations on any subject on which the House of Justice proposes to legislate always precedes its act of legislation. Second, the Universal House of Justice, itself assured of Divine guidance, is well aware of the absence of the Guardian and will approach all matters of legislation only when certain of its sphere of jurisdiction, a sphere which the Guardian has confidently described as "clearly defined." Third, we must not forget the Guardian's written statement about these two institutions: "Neither can, nor will ever, infringe upon the sacred and prescribed domain of the other."
- The Universal House of Justice (From a letter dated 27 May 1966, published in "Wellspring of Guidance: Messages 1963-1968"; The Compilation of Compilations, vol. I, The Covenant)
