Sahih al-Bukhari Book 10, Hadith 78
Allah's Messenger (ﷺ) went to establish peace among Bani `Amr bin `Auf. In the meantime the time of
prayer was due and the Mu'adh-dhin went to Abu Bakr and said, "Will you lead the prayer, so that I
may pronounce the Iqama?" Abu Bakr replied in the affirmative and led the prayer. Allah's Messenger (ﷺ)
came while the people were still praying and he entered the rows of the praying people till he stood in
the (first row). The people clapped their hands. Abu Bakr never glanced sideways in his prayer but
when the people continued clapping, Abu Bakr looked and saw Allah's Messenger (ﷺ). Allah's Messenger (ﷺ)
beckoned him to stay at his place. Abu Bakr raised his hands and thanked Allah for that order of
Allah's Messenger (ﷺ) and then he retreated till he reached the first row. Allah's Messenger (ﷺ) went forward and
led the prayer. When Allah's Messenger (ﷺ) finished the prayer, he said, "O Abu Bakr! What prevented you
from staying when I ordered you to do so?"
Abu Bakr replied, "How can Ibn Abi Quhafa (Abu Bakr) dare to lead the prayer in the presence of
Allah's Messenger (ﷺ)?" Then Allah's Messenger (ﷺ) said, "Why did you clap so much? If something happens to
anyone during his prayer he should say Subhan Allah. If he says so he will be attended to, for clapping
is for women."
`Aisha said, "Allah's Messenger (ﷺ) ordered Abu Bakr to lead the people in the prayer during his illness and so he led them in prayer." `Urwa, a sub narrator, added, "Allah's Messenger (ﷺ) felt a bit relieved and came out and Abu Bakr was leading the people. When Abu Bakr saw the Prophet (ﷺ) he retreated but the Prophet beckoned him to remain there. Allah's Messenger (ﷺ) sat beside Abu Bakr. Abu Bakr was following the prayer of Allah's Messenger (ﷺ) and the people were following the prayer of Abu Bakr."
We went to the Prophet (ﷺ) and we were all young men and stayed with him for about twenty nights. The Prophet (ﷺ) was very merciful. He said, "When you return home, impart religious teachings to your families and tell them to offer perfectly such and such a prayer at such and such a time and such and such a prayer at such and such a time. And at the time of the prayer one of you should pronounce the Adhan and the oldest of you should lead the prayer."