The Messenger of Allah wiped over his leather socks and his head cover (i.e., over the Imamah).  

أَنَّ رَسُولَ اللَّهِ ﷺ مَسَحَ عَلَى الْخُفَّيْنِ وَالْخِمَارِ  

"I saw the Messenger of Allah wiping over his leather socks and turban."  

رَأَيْتُ رَسُولَ اللَّهِ ﷺ يَمْسَحُ عَلَى الْخُفَّيْنِ وَالْعِمَامَةِ  

"I was with Salman, and he saw a man removing his leather socks for ablution. Salman said to him" 'Wipe over your leather socks and your head cover, and your forehead, for I saw the Messenger of Allah wiping over his leather socks and head cover.'"  

كُنْتُ مَعَ سَلْمَانَ فَرَأَى رَجُلاً يَنْزِعُ خُفَّيْهِ لِلْوُضُوءِ فَقَالَ لَهُ سَلْمَانُ امْسَحْ عَلَى خُفَّيْكَ وَعَلَى خِمَارِكَ وَبِنَاصِيَتِكَ فَإِنِّي رَأَيْتُ رَسُولَ اللَّهِ ﷺ يَمْسَحُ عَلَى الْخُفَّيْنِ وَالْخِمَارِ  

"I saw the Messenger of Allah performing ablution, wearing a Qatari turban. He put his hand beneath the turban and wiped the front part of his head, and he did not take the turban off."  

رَأَيْتُ رَسُولَ اللَّهِ ﷺ تَوَضَّأَ وَعَلَيْهِ عِمَامَةٌ قِطْرِيَّةٌ فَأَدْخَلَ يَدَهُ مِنْ تَحْتِ الْعِمَامَةِ فَمَسَحَ مُقَدَّمَ رَأْسِهِ وَلَمْ يَنْقُضِ الْعِمَامَةَ