A. L. M. Nicolas quotes the following from the
Kitabu’l-Haramayn: “In truth, the first day that the Spirit descended in the
heart of this Slave was the fifteenth of the month of Rabí’u’l-Avval.” (A. L.
M. Nicolas’ “Siyyid ‘Alí-Muhammad dit le Báb,” p. 206.)
(Footnotes to chapter 3
of ‘The Dawn-Breakers’, provided by Shoghi Effendi)