Not to use ‘Abdu’l-Baha’s public talks and Tablets at Baha’i Temples

It is permissible and satisfactory to use the Prayers of 'Abdu'l-Bahá in the devotional services in the Temple. His public talks and Tablets should not be used, but His prayers may be used.

It is understood of course that there is to be no talking in the auditorium of the Temple. However, the Guardian does feel that in an emergency it may be necessary to carry on a conversation for a very limited period, in a subdued tone of voice. The Guardian feels that in matters of this type, careful judgment must be used. 

- Shoghi Effendi  (From a letter dated 3 October 1953 written on behalf of Shoghi Effendi to the National Spiritual Assembly of the United States; The Compilation of Compilations, vol. III, Service in Baha’i Temples)