[Machine] That the Prophet ﷺ prayed behind Abu Bakr once. Al-Shafi'i, may Allah have mercy on him, said: "If the Messenger of Allah ﷺ had prayed behind Abu Bakr once, that would not prevent Abu Bakr from praying behind him another time." The scholar said: "Musa ibn 'Uqbah had already set out for his expeditions until Abu Bakr prayed a Rak'ah after the Fajr prayer on Monday, the day on which the Prophet ﷺ passed away. The Prophet ﷺ felt lighter and he went out and prayed a Rak'ah with Abu Bakr. When Abu Bakr finished praying, he stood and prayed another Rak'ah. It is possible that this prayer is what is meant by the one who narrated that he prayed behind Abu Bakr during his illness. As for the prayer that Abu Bakr prayed behind the Prophet ﷺ during his illness, it was the Dhuhr prayer on Sunday or Saturday, as we have narrated from Aisha and Ibn Abbas in explaining the Dhuhr prayer. There is no contradiction between the two, and it is permissible to argue based on the earlier report.  

أَنَّ النَّبِيَّ ﷺ صَلَّى خَلْفَ أَبِي بَكْرٍ ؓ قَالَ الشَّافِعِيُّ رَحِمَهُ اللهُ لَوْ صَلَّى رَسُولُ اللهِ ﷺ خَلْفَ أَبِي بَكْرٍ مَرَّةً لَمْ يَمْنَعْ ذَلِكَ أَنْ يَكُونَ صَلَّى خَلْفَهُ أَبُو بَكْرٍ أُخْرَى قَالَ الشَّيْخُ وَقَدْ ذَهَبَ مُوسَى بْنُ عُقْبَةَ فِي مَغَازِيهِ إِلَى أَنَّ أَبَا بَكْرٍ صَلَّى مِنْ صَلَاةِ الصُّبْحِ يَوْمَ الِاثْنَيْنِ رَكْعَةً وَهُوَ الْيَوْمُ الَّذِي تُوُفِّيَ فِيهِ النَّبِيُّ ﷺ فَوَجَدَ النَّبِيُّ ﷺ فِي نَفْسِهِ خِفَّةً فَخَرَجَ فَصَلَّى مَعَ أَبِي بَكْرٍ رَكْعَةً فَلَمَّا سَلَّمَ أَبُو بَكْرٍ قَامَ فَصَلَّى الرَّكْعَةَ الْأُخْرَى فَيُحْتَمَلُ أَنْ تَكُونَ هَذِهِ الصَّلَاةُ مُرَادَ مَنْ رَوَى أَنَّهُ صَلَّى خَلْفَ أَبِي بَكْرٍ فِي مَرَضِهِ فَأَمَّا الصَّلَاةُ الَّتِي صَلَّاهَا أَبُو بَكْرٍ خَلْفَهُ فِي مَرَضِهِ فَهِيَ صَلَاةُ الظُّهْرِ يَوْمَ الْأَحَدِ أَوْ يَوْمَ السَّبْتِ كَمَا رُوِّينَا عَنْ عَائِشَةَ وَابْنِ عَبَّاسٍ فِي بَيَانِ الظُّهْرِ فَلَا تَكُونُ بَيْنَهُمَا مُنَافَاةٌ وَيَصِحُّ الِاحْتِجَاجُ بِالْخَبَرِ الْأَوَّلِ