The Imam is appointed to be followed

Narrated 'Ubaid-Ullah Ibn 'Abdullah bin 'Utba:

I went to 'Aisha and asked her to describe to me the illness of Allah's Apostle. 'Aisha said, "Yes. The Prophet became seriously ill and asked whether the people had prayed. We replied, 'No. O Allah's Apostle! They are waiting for you.' He added, 'Put water for me in a trough." 'Aisha added, "We did so. He took a bath and tried to get up but fainted. When he recovered, he again asked whether the people had prayed. We said, 'No, they are waiting for you. O Allah's Apostle,' He again said, 'Put water in a trough for me.' He sat down and took a bath and tried to get up but fainted again. Then he recovered and said, 'Have the people prayed?' We replied, 'No, they are waiting for you. O Allah's Apostle.' He said, 'Put water for me in the trough.' Then he sat down and washed himself and tried to get up but he fainted. When he recovered, he asked, 'Have the people prayed?' We said, 'No, they are waiting for you. O Allah's Apostle! The people were in the mosque waiting for the Prophet for the 'Isha prayer. The Prophet sent for Abu Bakr to lead the people in the prayer. The messenger went to Abu Bakr and said, 'Allah's Apostle orders you to lead the people in the prayer.' Abu Bakr was a soft-hearted man, so he asked 'Umar to lead the prayer but 'Umar replied, 'You are more rightful.' So Abu Bakr led the prayer in those days. When the Prophet felt a bit better, he came out for the Zuhr prayer with the help of two persons one of whom was Al-'Abbas. while Abu Bakr was leading the people in the prayer. When Abu Bakr saw him he wanted to retreat but the Prophet beckoned him not to do so and asked them to make him sit beside Abu Bakr and they did so. Abu Bakr was following the Prophet (in the prayer) and the people were following Abu Bakr. The Prophet (prayed) sitting." 'Ubaid-Ullah added "I went to 'Abdullah bin 'Abbas and asked him, Shall I tell you what Aisha has told me about the fatal illness of the Prophet?' Ibn 'Abbas said, 'Go ahead. I told him her narration and he did not deny anything of it but asked whether 'Aisha told me the name of the second person (who helped the Prophet ) along with Al-Abbas. I said. 'No.' He said, 'He was 'Ali (Ibn Abi Talib).

حَدَّثَنَا أَحْمَدُ بْنُ يُونُسَ، قَالَ حَدَّثَنَا زَائِدَةُ، عَنْ مُوسَى بْنِ أَبِي عَائِشَةَ، عَنْ عُبَيْدِ اللَّهِ بْنِ عَبْدِ اللَّهِ بْنِ عُتْبَةَ، قَالَ دَخَلْتُ عَلَى عَائِشَةَ فَقُلْتُ أَلاَ تُحَدِّثِينِي عَنْ مَرَضِ رَسُولِ اللَّهِ ﷺ قَالَتْ بَلَى، ثَقُلَ النَّبِيُّ ﷺ فَقَالَ " أَصَلَّى النَّاسُ ". قُلْنَا لاَ، هُمْ يَنْتَظِرُونَكَ. قَالَ " ضَعُوا لِي مَاءً فِي الْمِخْضَبِ ". قَالَتْ فَفَعَلْنَا فَاغْتَسَلَ فَذَهَبَ لِيَنُوءَ فَأُغْمِيَ عَلَيْهِ، ثُمَّ أَفَاقَ فَقَالَ ﷺ " أَصَلَّى النَّاسُ ". قُلْنَا لاَ، هُمْ يَنْتَظِرُونَكَ يَا رَسُولَ اللَّهِ. قَالَ " ضَعُوا لِي مَاءً فِي الْمِخْضَبِ ". قَالَتْ فَقَعَدَ فَاغْتَسَلَ، ثُمَّ ذَهَبَ لِيَنُوءَ فَأُغْمِيَ عَلَيْهِ، ثُمَّ أَفَاقَ فَقَالَ " أَصَلَّى النَّاسُ ". قُلْنَا لاَ، هُمْ يَنْتَظِرُونَكَ يَا رَسُولَ اللَّهِ. فَقَالَ " ضَعُوا لِي مَاءً فِي الْمِخْضَبِ "، فَقَعَدَ فَاغْتَسَلَ، ثُمَّ ذَهَبَ لِيَنُوءَ فَأُغْمِيَ عَلَيْهِ، ثُمَّ أَفَاقَ فَقَالَ " أَصَلَّى النَّاسُ ". فَقُلْنَا لاَ، هُمْ يَنْتَظِرُونَكَ يَا رَسُولَ اللَّهِ ـ وَالنَّاسُ عُكُوفٌ فِي الْمَسْجِدِ يَنْتَظِرُونَ النَّبِيَّ عَلَيْهِ السَّلاَمُ لِصَلاَةِ الْعِشَاءِ الآخِرَةِ ـ فَأَرْسَلَ النَّبِيُّ ﷺ إِلَى أَبِي بَكْرٍ بِأَنْ يُصَلِّيَ بِالنَّاسِ، فَأَتَاهُ الرَّسُولُ فَقَالَ إِنَّ رَسُولَ اللَّهِ ﷺ يَأْمُرُكَ أَنْ تُصَلِّيَ بِالنَّاسِ. فَقَالَ أَبُو بَكْرٍ ـ وَكَانَ رَجُلاً رَقِيقًا ـ يَا عُمَرُ صَلِّ بِالنَّاسِ. فَقَالَ لَهُ عُمَرُ أَنْتَ أَحَقُّ بِذَلِكَ. فَصَلَّى أَبُو بَكْرٍ تِلْكَ الأَيَّامَ، ثُمَّ إِنَّ النَّبِيَّ ﷺ وَجَدَ مِنْ نَفْسِهِ خِفَّةً فَخَرَجَ بَيْنَ رَجُلَيْنِ أَحَدُهُمَا الْعَبَّاسُ لِصَلاَةِ الظُّهْرِ، وَأَبُو بَكْرٍ يُصَلِّي بِالنَّاسِ، فَلَمَّا رَآهُ أَبُو بَكْرٍ ذَهَبَ لِيَتَأَخَّرَ فَأَوْمَأَ إِلَيْهِ النَّبِيُّ ﷺ بِأَنْ لاَ يَتَأَخَّرَ. قَالَ " أَجْلِسَانِي إِلَى جَنْبِهِ ". فَأَجْلَسَاهُ إِلَى جَنْبِ أَبِي بَكْرٍ. قَالَ فَجَعَلَ أَبُو بَكْرٍ يُصَلِّي وَهْوَ يَأْتَمُّ بِصَلاَةِ النَّبِيِّ ﷺ وَالنَّاسُ بِصَلاَةِ أَبِي بَكْرٍ، وَالنَّبِيُّ ﷺ قَاعِدٌ. قَالَ عُبَيْدُ اللَّهِ فَدَخَلْتُ عَلَى عَبْدِ اللَّهِ بْنِ عَبَّاسٍ فَقُلْتُ لَهُ أَلاَ أَعْرِضُ عَلَيْكَ مَا حَدَّثَتْنِي عَائِشَةُ عَنْ مَرَضِ النَّبِيِّ ﷺ قَالَ هَاتِ. فَعَرَضْتُ عَلَيْهِ حَدِيثَهَا، فَمَا أَنْكَرَ مِنْهُ شَيْئًا، غَيْرَ أَنَّهُ قَالَ أَسَمَّتْ لَكَ الرَّجُلَ الَّذِي كَانَ مَعَ الْعَبَّاسِ قُلْتُ لاَ. قَالَ هُوَ عَلِيٌّ.

Narrated Aisha:

the mother of the believers: Allah's Apostle during his illness prayed at his house while sitting whereas some people prayed behind him standing. The Prophet beckoned them to sit down. On completion of the prayer, he said, 'The Imam is to be followed: bow when he bows, raise up your heads (stand erect) when he raises his head and when he says, 'Sami a-l-lahu liman-hamida ' (Allah heard those who sent praises to Him) say then 'Rabbana wa laka-l-hamd' (O our Lord! All the praises are for You), and if he prays sitting then pray sitting."

حَدَّثَنَا عَبْدُ اللَّهِ بْنُ يُوسُفَ، قَالَ أَخْبَرَنَا مَالِكٌ، عَنْ هِشَامِ بْنِ عُرْوَةَ، عَنْ أَبِيهِ، عَنْ عَائِشَةَ أُمِّ الْمُؤْمِنِينَ، أَنَّهَا قَالَتْ صَلَّى رَسُولُ اللَّهِ ﷺ فِي بَيْتِهِ وَهْوَ شَاكٍ، فَصَلَّى جَالِسًا وَصَلَّى وَرَاءَهُ قَوْمٌ قِيَامًا، فَأَشَارَ إِلَيْهِمْ أَنِ اجْلِسُوا، فَلَمَّا انْصَرَفَ قَالَ " إِنَّمَا جُعِلَ الإِمَامُ لِيُؤْتَمَّ بِهِ، فَإِذَا رَكَعَ فَارْكَعُوا، وَإِذَا رَفَعَ فَارْفَعُوا، وَإِذَا صَلَّى جَالِسًا فَصَلُّوا جُلُوسًا ".