Hadith 1908

أَخْبَرَنِي مُحَمَّدُ بْنُ عَبْدِ اللَّهِ بْنِ عَبْدِ الْحَكَمِ ، أَنَّ ابْنَ وَهْبٍ أَخْبَرَهُمْ ، قَالَ : وَأَخْبَرَنِي يُونُسُ ، عَنِ ابْنِ شِهَابٍ ، عَنْ أَبِي سَلَمَةَ ، عَنْ أَبِي هُرَيْرَةَ ، عَنْ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ نَحْوَ خَبَرِ ابْنِ عُمَرَ ، فَقَالَ : " فَإِنْ غُمَّ عَلَيْكُمْ فَعُدُّوا ثَلاثِينَ "
Sayyiduna Abu Hurairah (may Allah be pleased with him) narrates from the Messenger of Allah (peace and blessings of Allah be upon him) in the same manner as Sayyiduna Ibn Umar (may Allah be pleased with them both). The Prophet (peace and blessings of Allah be upon him) said: "Then if clouds cover you, count (the month of Sha'ban as) thirty days."
Hadith Reference صحيح ابن خزيمه / 1908