سنن أبي داود

Narrated Abdullah ibn Zam'ah:

When the illness of the Messenger of Allah (ﷺ) became serious while I was with him among a group of people, Bilal called him for prayer. He said: Ask someone to lead the people in prayer. So Abdullah ibn Zam'ah went out and found that Umar was present among the people and AbuBakr was not there. I said: Umar, get up and lead the people in prayer. So he came forward and uttered "Allah is Most Great". When the Messenger of Allah (ﷺ) heard his voice, as Umar had a loud voice, he said: Where is AbuBakr? Allah does not allow that, and the Muslims too; Allah does not allow that, and the Muslims too. So he sent for AbuBakr. He came after Umar had led the people in that prayer. He then led the people in prayer.