Sahih Bukhari Volume 004, Book 056, Hadith Number 785.
Hadith Section/Book: Sahih Bukhari Sahih Bukhari Book 56. Virtues and Merits of the Prophets (PBUH) and his Companions
Narated By Anas bin Malik : That he heard Jabir bin 'Abdullah saying, "The roof of the Mosque was built over trunks of date-palms working as pillars. When the Prophet delivered a sermon, he used to stand by one of those trunks till the pulpit was made for him, and he used it instead. Then we heard the trunk sending a sound like of a pregnant she-camel till the Prophet came to it, and put his hand over it, then it became quiet."