Sahih Muslim 553
Sahih Muslim · Book 5: The Book of Mosques and Places of Prayer · The prohibition of spitting in the masjid, during prayer and at other times. The prohibition of a praying person spitting in front of him or to his right
Abu Dharr reported:
حَدَّثَنَا عَبْدُ اللَّهِ بْنُ مُحَمَّدِ بْنِ أَسْمَاءَ الضُّبَعِيُّ ، وَشَيْبَانُ بْنُ فَرُّوخَ، قَالاَ حَدَّثَنَا مَهْدِيُّ بْنُ مَيْمُونٍ ، حَدَّثَنَا وَاصِلٌ ، مَوْلَى أَبِي عُيَيْنَةَ عَنْ يَحْيَى بْنِ عُقَيْلٍ ، عَنْ يَحْيَى بْنِ يَعْمَرَ ، عَنْ أَبِي الأَسْوَدِ الدِّيلِيِّ ، عَنْ أَبِي ذَرٍّ ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ " عُرِضَتْ عَلَىَّ أَعْمَالُ أُمَّتِي حَسَنُهَا وَسَيِّئُهَا فَوَجَدْتُ فِي مَحَاسِنِ أَعْمَالِهَا الأَذَى يُمَاطُ عَنِ الطَّرِيقِ وَوَجَدْتُ فِي مَسَاوِي أَعْمَالِهَا النُّخَاعَةَ تَكُونُ فِي الْمَسْجِدِ لاَ تُدْفَنُ " .
The Apostle of Allah (ﷺ) said: The deeds of my people, good and bad, were presented before me, and I found the removal of something objectionable from the road among their good deeds, and the sputum mucus left unburied in the mosque among their evil deeds.