Sahih Bukhari Volume 002, Book 022, Hadith Number 309.
Narated By Sahl bin Sad : The news about the differences amongst the people of Bani 'Amr bin 'Auf at Quba reached Allah's Apostle and so he went to them along with some of his companions to affect a reconciliation. Allah's Apostle was delayed there and the time for the prayer became due. Bilal came to Abu Bakr! and said, "O Abu Bakr! Allah's Apostle is detained (there) and the time for the prayer is due. Will you lead the people in prayer?" Abu Bakr replied, "Yes, if you wish." So Bilal pronounced the Iqama and Abu Bakr went forward and the people said Takbir. In the meantime, Allah's Apostle came piercing through the rows till he stood in the (first) row and the people started clapping. Abu Bakr, would never look hither and thither during the prayer but when the people clapped much he looked back and saw Allah's Apostle. The Prophet beckoned him to carry on. Abu Bakr raised both his hands, praised Allah and retreated till he stood in the row and Allah's Apostle went forward and led the people in the prayer. When he had finished the prayer, he addressed the people and said, "O people! Why did you start clapping when something happened to you in the prayer? Clapping is for women. Whenever one is confronted with something unusual in the prayer one should say, 'Sub Han Allah'." Then the Prophet looked towards Abu Bakr and asked, "What prevented you from leading the prayer when I beckoned you to carry on?" Abu Bakr replied, "It does not befit the son of Al Quhafa to lead the prayer in the presence of Allah's Apostle."