The Book of Fasting
22/9. Chapter:
Completing thirty days Of Sha'ban if it is obscured (cloudy) and mentioning the differences reported by the narrators from Abu Hurairah
Sunan an-Nasai
أَخْبَرَنَا مُحَمَّدُ بْنُ عَبْدِ اللَّهِ بْنِ يَزِيدَ، قَالَ حَدَّثَنَا أَبِي قَالَ، حَدَّثَنَا وَرْقَاءُ، عَنْ شُعْبَةَ، عَنْ مُحَمَّدِ بْنِ زِيَادٍ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " صُومُوا لِرُؤْيَتِهِ وَأَفْطِرُوا لِرُؤْيَتِهِ فَإِنْ غُمَّ عَلَيْكُمْ فَاقْدُرُوا ثَلاَثِينَ " .
Narrated It was narrated that Abu Hurairah said: : "The Messenger of Allah said: 'Fast when you see it and stop fasting when you see it, and if it is obscured from you (too cloudy), then count it as thirty (days).'"
Reference : Sunan an-Nasa'i 2118In-book reference : Book 22, Hadith 29English translation : Vol. 1, Book 22, Hadith 2120