It was narrated that Abul-Bakhtari said:
‘Umar said to Abu ‘Ubaidah bin al-Jarrah: Stretch out your hand so that I may give my allegiance to you, for I heard the Messenger of Allah (ﷺ) say: “You are the trustee of this ummah.” Abu ‘Ubaidah said: I will not put myself ahead of someone whom the Messenger of Allah (ﷺ) told to lead us in prayer and he led us in prayer until he [the Messenger of Allah (ﷺ)] died.