Musnad Ahmad 233
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.
حَدَّثَنَا مُحَمَّدُ بْنُ فُضَيْلٍ، حَدَّثَنَا إِسْمَاعِيلُ بْنُ سُمَيْعٍ، عَنْ مُسْلِمٍ الْبَطِينِ، عَنْ أَبِي الْبَخْتَرِيِّ، قَالَ قَالَ عُمَرُ لِأَبِي عُبَيْدَةَ بْنِ الْجَرَّاحِ ابْسُطْ يَدَكَ حَتَّى أُبَايِعَكَ فَإِنِّي سَمِعْتُ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَقُولُ أَنْتَ أَمِينُ هَذِهِ الْأُمَّةِ فَقَالَ أَبُو عُبَيْدَةَ مَا كُنْتُ لِأَتَقَدَّمَ بَيْنَ يَدَيْ رَجُلٍ أَمَرَهُ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ أَنْ يَؤُمَّنَا فَأَمَّنَا حَتَّى مَاتَ‏.‏