كتاب الصلاة
Read the English translation first, with the original Arabic directly underneath.
Anas reported:
The Messenger of Allah (ﷺ) said: Spitting in the mosque is a sin and it is expiated by burying the spittle.
الْبُزَاقُ فِي الْمَسْجِدِ خَطِيئَةٌ وَكَفَّارَتُهَا دَفْنُهَا