The Messenger of Allah saw some sputum on the wall of the mosque. He picked up a stone and scraped it off, then he said, "If anyone of you needs to spit, he should not spit in fro not of him or to his right; let him spit to his right; let him spit to his left or under his left foot."
عَنْ أَبِي هُرَيْرَةَ وَأَبِي سَعِيدٍ الْخُدْرِيِّ أَنَّهُمَا أَخْبَرَاهُ أَنَّ رَسُولَ اللَّهِ ﷺ رَأَى نُخَامَةً فِي جِدَارِ الْمَسْجِدِ فَتَنَاوَلَ حَصَاةً فَحَكَّهَا ثُمَّ قَالَ إِذَا تَنَخَّمَ أَحَدُكُمْ فَلاَ يَتَنَخَّمَنَّ قِبَلَ وَجْهِهِ وَلاَ عَنْ يَمِينِهِ وَلْيَبْزُقْ عَنْ شِمَالِهِ أَوْ تَحْتَ قَدَمِهِ الْيُسْرَى