Sahih Muslim Book - 5, Hadith - 1228

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

It was narrated from Abu Hurairah that the Messenger of Allah (s.a.w) saw some sputum in the Qiblah of the Masjid. He turned to the people and said: "What is the matter with one of you who stands before his Lord and spits in front of him? Would any one of you like to have someone stand before him and spit in his face? If one of you must spit, then let him spit to his left, beneath his foot. If he cannot do that, then let him do like this," and Al-Qasim described how he spat into his garment then rubbed part of it against another part.