Sunan an-Nasa'i 2123
سنن النسائي#2123Sahihأَخْبَرَنَا أَبُو بَكْرِ بْنُ عَلِيٍّ، صَاحِبُ حِمْصَ قَالَ حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، قَالَ حَدَّثَنَا مُحَمَّدُ بْنُ بِشْرٍ، قَالَ حَدَّثَنَا عُبَيْدُ اللَّهِ، عَنْ أَبِي الزِّنَادِ، عَنِ الأَعْرَجِ، عَنْ أَبِي هُرَيْرَةَ، قَالَ ذَكَرَ رَسُولُ اللَّهِ صلى الله عليه وسلم الْهِلاَلَ فَقَالَ " إِذَا رَأَيْتُمُوهُ فَصُومُوا وَإِذَا رَأَيْتُمُوهُ فَأَفْطِرُوا فَإِنْ غُمَّ عَلَيْكُمْ فَعُدُّوا ثَلاَثِينَ " .
It was narrated that Abu Hurairah said:"The Messenger of Allah mentioned the crescent and said: 'When you see it, fast and when you see it, stop fasting, and if it is obscured from you (too cloudy), then count thirty days
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:
In-book reference: 22:34