Sahih Muslim , Hadith 552 ⓘ
Anas b. Malik reported: The Messenger of Allah said: Spitting in a mosque is a sin, and its expiation is that it should be buried.
وَحَدَّثَنَا يَحْيَى بْنُ يَحْيَى، وَقُتَيْبَةُ بْنُ سَعِيدٍ، قَالَ يَحْيَى أَخْبَرَنَا وَقَالَ، قُتَيْبَةُ حَدَّثَنَا أَبُو عَوَانَةَ، عَنْ قَتَادَةَ، عَنْ أَنَسِ بْنِ مَالِكٍ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " الْبُزَاقُ فِي الْمَسْجِدِ خَطِيئَةٌ وَكَفَّارَتُهَا دَفْنُهَا " .
also referenced under: Book 5, Hadith 69 (In-Book) & Book 4, Hadith 1124 (USC-MSA)
Shu'ba reported: I asked Qatada about spitting, in the mosque. He said: I heard Anas b. Malik say: I heard the Messenger of Allah say: Spitting in the mosque is a sin, and its expiation is that it should be buried.
حَدَّثَنَا يَحْيَى بْنُ حَبِيبٍ الْحَارِثِيُّ، حَدَّثَنَا خَالِدٌ، - يَعْنِي ابْنَ الْحَارِثِ - حَدَّثَنَا شُعْبَةُ، قَالَ سَأَلْتُ قَتَادَةَ عَنِ التَّفْلِ، فِي الْمَسْجِدِ فَقَالَ سَمِعْتُ أَنَسَ بْنَ مَالِكٍ، يَقُولُ سَمِعْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم يَقُولُ " التَّفْلُ فِي الْمَسْجِدِ خَطِيئَةٌ وَكَفَّارَتُهَا دَفْنُهَا " .
also referenced under: Book 5, Hadith 70 (In-Book) & Book 4, Hadith 1125 (USC-MSA)