Sunan Ibn Majah 764
سنن ابن ماجه#764Sahihحَدَّثَنَا عَلِيُّ بْنُ مُحَمَّدٍ، حَدَّثَنَا وَكِيعٌ، عَنْ هِشَامِ بْنِ عُرْوَةَ، عَنْ أَبِيهِ، عَنْ عَائِشَةَ، أَنَّ النَّبِيَّ ـ صلى الله عليه وسلم ـ حَكَّ بُزَاقًا فِي قِبْلَةِ الْمَسْجِدِ .
It was narrated from 'Aishah that:The Prophet scratched some spittle from the prayer direction of the mosque
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
Al-AlbaniSahih
Muhammad Fouad Abd al-BaqiSahih
Shuaib Al ArnautSahih
Zubair Ali ZaiIsnaad Sahih
In-book reference: 4:30