Sunan Ibn Majah 1654
سنن ابن ماجه#1654Sahihحَدَّثَنَا أَبُو مَرْوَانَ، مُحَمَّدُ بْنُ عُثْمَانَ الْعُثْمَانِيُّ حَدَّثَنَا إِبْرَاهِيمُ بْنُ سَعْدٍ، عَنِ الزُّهْرِيِّ، عَنْ سَالِمِ بْنِ عَبْدِ اللَّهِ، عَنِ ابْنِ عُمَرَ، قَالَ: قَالَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ " إِذَا رَأَيْتُمُ الْهِلاَلَ فَصُومُوا وَإِذَا رَأَيْتُمُوهُ فَأَفْطِرُوا . فَإِنْ غُمَّ عَلَيْكُمْ فَاقْدُرُوا لَهُ " . وَكَانَ ابْنُ عُمَرَ يَصُومُ قَبْلَ الْهِلاَلِ بِيَوْمٍ .
It was narrated from Ibn ‘Umar that the Messenger of Allah (ﷺ) said:‘When you see the new crescent, fast, and when you see it, stop fasting. If it is cloudy then calculate it (as thirty days).” Ibn ‘Umar used to fast one day before the new crescent was seen
Scholarly Authentication
The label above is the grade most of these scholars gave, each scholar counted once — 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. When they judged only its chain of narrators (“Isnaad”), the label says “Sound chain”. Each scholar's own wording:
Our source also lists this ruling under Muhammad Fouad Abd al-Baqi, the editor of the printed edition it was taken from. It is al-Albani's ruling printed again, so it is counted once.
In-book reference: 7:17