Yahya related to me from Malik from Hisham ibn Urwa from his father from A'isha, the wife of the Prophet, mayAllah bless him and grant him peace, that the Prophet ﷺ saw spittle, or mucus or phlegm, on the wall of the qibla and scraped it off.
أنَّ رَسُولَ اللهِ رَأى فِي جِدارِ القِبْلَةَ بُصاقًا، أوْ مُخاطًا، أوْ نُخامَةً، فَحَكَّهُ.