[Machine] There are two qualities that I do not ask anyone about after witnessing them with the Messenger of Allah ﷺ : wiping over the footwear during ablution (masah al-khufayn) and the prayer of an imam behind some of his followers. We were traveling with the Messenger of Allah and stopped at a place. The Prophet ﷺ went aside to attend to his needs, and when he was done, I brought him some water. He performed ablution with a tight-sleeved caftan on, and he wiped over his forehead, turban, and footwear. Then, we joined the people who were praying. The people had already been led in prayer by Abdur-Rahman bin Auf, so we caught up with them and the Messenger of Allah completed the second rak'ah.  

خَصْلَتَانِ لَا أَسْأَلُ عَنْهُمَا أَحَدًا بَعْدَ أَنْ شَهِدْتُهُمَا مَعَ رَسُولِ الله ﷺ الْمَسْحُ عَلَى الْخُفَّيْنِ وَصَلَاةُ إِمَامٍ خَلْفَ بَعْضِ رَعِيَّتِهِ كُنَّا مَعَ رَسُولِ اللهِ فِي سَفَرٍ فَنَزَلْنَا مَنْزِلًا فَتَبَرَّزَ النَّبِيُّ ﷺ لِبَعْضِ حَاجَتِهِ فَلَمَّا قَضَى حَاجَتَهُ أَتَيْتُهُ بِمَاءٍ فَتَوَضَّأَ وَعَلَيْهِ جُبَّةٌ ضَيِّقَةُ الْكُمَّيْنِ فَأَخْرَجَ يَدَهُ مِنْ تَحْتِ الْجُبَّةِ وَمَسَحَ عَلَى نَاصِيَتِهِ وَعَلَى عِمَامَتِهِ وَعَلَى خُفَّيْهِ ثُمَّ أَتَيْنَا الْقَوْمَ وَهُمْ يُصَلُّونَ وَقَدْ قَدَّمَ الْقَوْمُ عَبْدَ الرَّحْمَنِ بْنَ عَوْفٍ فَأَدْرَكْنَا مَعَهُمْ رَكْعَةً فَقَضَى رَسُولُ اللهِ ﷺ الرَّكْعَةَ الْأُخْرَى