حَدَّثَنَا يَحْيَى عَنْ عُبَيْدِ اللَّهِ أَخْبَرَنَا نَافِعٌ عَنِ ابْنِ عُمَرَ أَنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ رَأَى نُخَامَةً فِي قِبْلَةِ الْمَسْجِدِ فَحَتَّهَا ثُمَّ قَالَ إِذَا كَانَ أَحَدُكُمْ فِي الصَّلَاةِ فَلَا يَتَنَخَّمْ فَإِنَّ اللَّهَ تَعَالَى قِبَلَ وَجْهِ أَحَدِكُمْ فِي الصَّلَاةِ
مسند امام احمد بن حنبل · Hadith 5152
It was narrated from Ibn Umar that the Messenger of Allah (PBUH) saw some sputum in the qiblah of the mosque. He scratched it then he said: "If one of you is praying, let him not spit. for Allah is in front of one of you when he prays."
Sanad
حَدَّثَنَا يَحْيَى عَنْ عُبَيْدِ اللَّهِ أَخْبَرَنَا نَافِعٌ عَنِ ابْنِ عُمَرَ