Hadith
حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، حَدَّثَنَا الْفَرَجُ بْنُ فَضَالَةَ، عَنْ أَبِي سَعِيدٍ، قَالَ رَأَيْتُ وَاثِلَةَ بْنَ الأَسْقَعِ فِي مَسْجِدِ دِمَشْقَ بَصَقَ عَلَى الْبُورِيِّ ثُمَّ مَسَحَهُ بِرِجْلِهِ فَقِيلَ لَهُ لِمَ فَعَلْتَ هَذَا قَالَ لأَنِّي رَأَيْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم يَفْعَلُهُ .
Narrated Wathilah ibn al-Asqa': AbuSa'id said: I saw Wathilah ibn al-Asqa' in the mosque of Damascus. He spat at the mat and then rubbed it with his foot. He was asked: Why did you do so? He said: Because I saw the Messenger of Allah (ﷺ) doing so
Da'if · Al-Albani
Sunan Abi Dawud 484 ·Book 2, Hadith 94·Also available on sunnah.com·