Sunan Ibn Majah, Chapter: The Chapters of Establishing the Prayer and the Sunnah Regarding Them

that the Messenger of Allah (saw) 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." Hasan