Sunan Ibn Majah Book 5, Hadith 1022

حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا إِسْمَاعِيلُ ابْنُ عُلَيَّةَ، عَنِ الْقَاسِمِ بْنِ مِهْرَانَ، عَنْ أَبِي رَافِعٍ، عَنْ أَبِي هُرَيْرَةَ، أَنَّ رَسُولَ اللَّهِ ـ صلى الله عليه وسلم ـ رَأَى نُخَامَةً فِي قِبْلَةِ الْمَسْجِدِ فَأَقْبَلَ عَلَى النَّاسِ فَقَالَ ‏ "‏ مَا بَالُ أَحَدِكُمْ يَقُومُ مُسْتَقْبِلَهُ - يَعْنِي رَبَّهُ - فَيَتَنَخَّعُ أَمَامَهُ أَيُحِبُّ أَحَدُكُمْ أَنْ يُسْتَقْبَلَ فَيُتَنَخَّعَ فِي وَجْهِهِ إِذَا بَزَقَ أَحَدُكُمْ فَلْيَبْزُقَنَّ عَنْ شِمَالِهِ أَوْ لِيَقُلْ هَكَذَا فِي ثَوْبِهِ ‏"‏ ‏.‏ ثُمَّ أَرَانِي إِسْمَاعِيلُ يَبْزُقُ فِي ثَوْبِهِ ثُمَّ يَدْلُكُهُ ‏.‏

It was narrated from Abu Hurairah that the Messenger of Allah (ﷺ) saw some sputum in the direction of the Qiblah of the mosque. He turned to the people and said:“What is wrong with one of you that he stands facing Him (meaning his Lord) and spits in front of Him? Would anyone like to be faced by someone who spits in his face? If anyone of you needs to spit, then let him spit to his left, or let him do like this in his garment.” Then Ismail (Abu Bakr bin Abu Shuaibah) showed me how he spat in his garment then rubbed it