Prayer (Kitab Al-Salat)
2/26. Chapter:
Spitting In A Masjid Is Disliked
Sunan Abi Dawud
حَدَّثَنَا مُسَدَّدٌ، حَدَّثَنَا أَبُو عَوَانَةَ، عَنْ قَتَادَةَ، عَنْ أَنَسِ بْنِ مَالِكٍ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " الْبُزَاقُ فِي الْمَسْجِدِ خَطِيئَةٌ وَكَفَّارَتُهَا دَفْنُهَا " .
Anas reported: The Messenger of Allah (ﷺ) said: Spitting in the mosque is a sin and it is expiated by burying the spittle.
Reference : Sunan Abi Dawud 475In-book reference : Book 2, Hadith 85English translation : Book 2, Hadith 475