Bulugh al-Maram, Book 5, Hadith 653 (In-Book)

Al-Bukhari reported on the authority of Abu Hurairah, “Complete the days of Sha’ban as thirty days.”

وَلَهُ فِي حَدِيثِ أَبِي هُرَيْرَةَ ‏- رضى الله عنه ‏- { فَأَكْمِلُوا عِدَّةَ شَعْبَانَ ثَلَاثِينَ } 1‏.‏ ‏1 ‏- صحيح.‏ رواه البخاري ( 1909 )‏.‏

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also referenced under: Book 5, Hadith 674 (English)