Hadith 550 a - The Book of Mosques and Places of Prayer - Sahih Muslim - صحيح مسلم - Collection of Actions, Sayings and Teachings of Prophet Muhammad (صلى الله عليه و سلم) - Kutub as-Sittah

5. The Book of Mosques and Places of Prayer - كتاب الْمَسَاجِدِ وَمَوَاضِعِ الصَّلاَةِ

13) Chapter: Forbiddance To Spit In The Mosque While Engaged In Prayer

Abu Huraira reported that the Messenger of Allah (ﷺ) saw some sputum in the direction of the Qibla of the mosque. He turned towards people and said:

How Is it that someone amongst you stands before his Lord and then spits out in front of Him? Does any one of you like that he should be made to stand in front of someone and then spit at his face? So when any one of you spits, he must spit on his left side under his foot. But if he does not find (space to spit) he should do like this. Qasim (one of the narrators) spat in his cloth and then folded it and rubbed it.

Reference: 550 a
English reference: Book 4, Hadith 1121
In-book reference: Book 5, Hadith 66
Grade: Sahih
Read this hadith from Darussalam Collection

13) باب النَّهْىِ عَنِ الْبُصَاقِ، فِي الْمَسْجِدِ فِي الصَّلاَةِ وَغَيْرِهَا ‏‏

حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، وَزُهَيْرُ بْنُ حَرْبٍ، جَمِيعًا عَنِ ابْنِ عُلَيَّةَ، قَالَ زُهَيْرٌ حَدَّثَنَا ابْنُ عُلَيَّةَ، عَنِ الْقَاسِمِ بْنِ مِهْرَانَ، عَنْ أَبِي رَافِعٍ، عَنْ أَبِي هُرَيْرَةَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم رَأَى نُخَامَةً فِي قِبْلَةِ الْمَسْجِدِ فَأَقْبَلَ عَلَى النَّاسِ فَقَالَ ‏‏ ‏.‏ وَوَصَفَ الْقَاسِمُ فَتَفَلَ فِي ثَوْبِهِ ثُمَّ مَسَحَ بَعْضَهُ عَلَى بَعْضٍ ‏.‏ "‏ مَا بَالُ أَحَدِكُمْ يَقُومُ مُسْتَقْبِلَ رَبِّهِ فَيَتَنَخَّعُ أَمَامَهُ أَيُحِبُّ أَحَدُكُمْ أَنْ يُسْتَقْبَلَ فَيُتَنَخَّعَ فِي وَجْهِهِ فَإِذَا تَنَخَّعَ أَحَدُكُمْ فَلْيَتَنَخَّعْ عَنْ يَسَارِهِ تَحْتَ قَدَمِهِ فَإِنْ لَمْ يَجِدْ فَلْيَقُلْ هَكَذَا ‏"