‘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.
سَمِعْتُ رَسُولَ اللهِ ﷺ يَقُولُ أَنْتَ أَمِينُ هَذِهِ الْأُمَّةِ فَقَالَ أَبُو عُبَيْدَةَ مَا كُنْتُ لِأَتَقَدَّمَ بَيْنَ يَدَيْ رَجُلٍ أَمَرَهُ رَسُولُ اللهِ ﷺ أَنْ يَؤُمَّنَا فَأَمَّنَا حَتَّى مَاتَ