Bulugh al-Maram, Book 10, Hadith 1226 (In-Book)

'Abdullah bin 'Amir bin Rabi'ah narrated, 'I witnessed the time of Abu Bakr, 'Umar and 'Uthman (RAA), and those who came after them. I never saw them flogging a slave for Qadhf (false accusation of adultery) except forty lashes.' Related by Malik, and Ath-Thawri in his book al-Jami.'

وَعَنْ عَبْدِ اَللَّهِ بْنِ عَامِرٍ بْنِ رَبِيعَةَ قَالَ: { لَقَدْ أَدْرَكَتُ أَبَا بَكْرٍ, وَعُمَرَ, وَعُثْمَانَ رَضِيَ اَللَّهُ عَنْهُمْ, وَمِنْ بَعْدَهُمْ, فَلَمْ أَرَهُمْ يَضْرِبُونَ اَلْمَمْلُوكَ فِي اَلْقَذْفِ إِلَّا أَرْبَعِينَ } رَوَاهُ مَالِكٌ, وَالثَّوْرِيُّ فِي "جَامِعِهِ" (1593)‏.‏ ‏2 ‏- صحيح.‏ وهو في "الموطأ" (2 /8287)‏ بنحوه ولم يذكر أبا بكر.‏

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also referenced under: Book 10, Hadith 1265 (English)