Sahih Muslim 1224
صحيح مسلم#1224SahihIbn Umar reported that the Messenger of Allah (ﷺ) saw sputum sticking to the Qibla wall of the mosque, the rest of the hadith is the same
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih Muslim is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 5:62