The Messenger of Allah ﷺ noticed some phlegm on the wall of the mosque facing the qiblah and scraped it off with his hand. He then turned to the people, visibly angry, and said, "When one of you is in prayer, Allah the Exalted is before his face. So none of you should spit in front of himself during his prayer."
حدثنا محمد بن عبد الرحمن حدثنا أيوب عن نافع
أن رسول الله ﷺ أبصر نخامة في قبلة المسجد فحتها بيده ثم أقبل على الناس فتغيظ عليهم ثم قال إن الله تعالى تلقاء وجه أحدكم في صلاته فلا يتنخمن أحدكم قبل وجهه في صلاته