Bayan Al-Hadith › Sahih Muslim › The Book of Fasting
Sahih Muslim 1080aصحيح مسلم 1080a
حَدَّثَنَا يَحْيَى بْنُ يَحْيَى، قَالَ قَرَأْتُ عَلَى مَالِكٍ عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، - رضى الله عنهما - عَنِ النَّبِيِّ صلى الله عليه وسلم أَنَّهُ ذَكَرَ رَمَضَانَ فَقَالَ " لاَ تَصُومُوا حَتَّى تَرَوُا الْهِلاَلَ وَلاَ تُفْطِرُوا حَتَّى تَرَوْهُ فَإِنْ أُغْمِيَ عَلَيْكُمْ فَاقْدِرُوا لَهُ " .
Ibn Umar (Allah be pleased with both of them) reported Allah's Messenger (ﷺ) as saying in connection with Ramadan: Do not fast till you see the new moon, and do not break fast till you see it; but if the weather is cloudy calculate about it.
Grading
Sahih (authentic by the consensus of hadith scholars)
Chain of narrators
يحيى بن يحيى بن بكر ← نافع ← عبد الله بن عمر
Yahya ibn Yahya ibn Bakr → Nafi' → Ibn `Umar