I saw Wathila bin Asqa in the mosque of Damascus spit on the reed mat and then wipe it away with his foot. He was asked, "Why did you do this?"He replied, "Because I saw the Messenger of Allah ﷺ do it."
حدثنا قتيبة بن سعيد حدثنا الفرج بن فضالة
رأيت واثلة بن الأسقع في مسجد دمشق بصق على البوري ثم مسحه برجله فقيل له لم فعلت هذا قال لأني رأيت رسول الله ﷺ يفعله
No references are available.
Its chain is daif. Ahmad narrated it, 30/490, from the hadith of Faraj bin Fadala, and he is daif (Taqrib says the majority declared him daif), and his teacher is unknown.