We came to the Prophet ﷺ and stayed with him for twenty days and nights. We were all young and of about the same age. The Prophet ﷺ was very kind and merciful. When he realized our longing for our families, he asked about our homes and the people there and we told him. Then he asked us to go back to our families and stay with them and teach them (the religion) and to order them to do good things. He also mentioned some other things which I have (remembered or [??] ) forgotten. The Prophet ﷺ then added, "Pray as you have seen me praying and when it is the time for the prayer one of you should pronounce the Adhan and the oldest of you should lead the prayer. (Using translation from Bukhārī 631)   

أَتَيْنَا رَسُولَ اللهِ ﷺ وَنَحْنُ شَبَبَةٌ مُتَقَارِبُونَ فَأَقَمْنَا عِنْدَهُ عِشْرِينَ لَيْلَةً وَكَانَ رَسُولُ اللهِ ﷺ رَحِيمًا رَقِيقًا فَلَمَّا ظَنَّ أَنَّا قَدِ اشْتَهَيْنَا أَهْلِينَا وَاشْتَقْنَا سَأَلَنَا عَمَّا تَرَكْنَا بَعْدُ فَأَخْبَرَنَاهُ فَقَالَ ارْجِعُوا إِلَى أَهَالِيكُمْ فَأَقِيمُوا فِيهِمْ وَعَلِّمُوهُمْ وَمُرُوهُمْ وَذَكَرَ أَشْيَاءَ أَحْفَظُهَا وَأَشْيَاءَ لَا أَحْفَظُهَا وَصَلُّوا كَمَا رَأَيْتُمُونِي أُصَلِّي فَإِذَا حَضَرَتِ الصَّلَاةُ فَلْيُؤَذِّنْ لَكُمْ أَحَدُكُمْ وَلْيَؤُمَّكُمْ أَكْبَرُكُمْ  

When the time of prayer comes, call the Adhan, then call the iqamah, then the one who is oldest of you should act as your imam. The version narrated by Maslamah goes : He said: On that day we were almost equal in knowledge. The version narrated by Isma’il says: Khalid said: I said to Abu Qilabah: where is the Qur’an(i.e. why did the Prophet ﷺ not say: The one who knows the Qur’an most should act as imam)? He replied: Both of them were equal in the knowledge of the Qur’an. (Using translation from Abū Dāʾūd 589)   

أَنَّ النَّبِيَّ ﷺ قَالَ لَهُ أَوْ لِصَاحِبٍ لَهُ إِذَا حَضَرَتِ الصَّلَاةُ فَأَذِّنَا ثُمَّ أَقِيمَا ثُمَّ لِيَؤُمَّكُمَا أَكْبَرُكُمَا وَفِي حَدِيثِ مَسْلَمَةَ قَالَ كُنَّا يَوْمَئِذٍ مُتَقَارِبَيْنِ فِي الْعِلْمِ وَقَالَ فِي حَدِيثِ إِسْمَاعِيلَ قَالَ خَالِدٌ قُلْتُ لِأَبِي قِلَابَةَ فَأَيْنَ الْقِرَاءَةُ؟ قَالَ إِنَّهُمَا كَانَا مُتَقَارِبَيْنِ