Imam Shafi’i, may Allah have mercy on him, says that a trustworthy person from the people of Madinah informed about Zuhri, may Allah have mercy on him, that he narrates from Sa’id bin al-Musayyib, may Allah have mercy on him: When Sayyiduna ‘Umar, may Allah be pleased with him, flogged three men, he asked them to repent. Two of them repented, so their testimony began to be accepted. Abu Bakrah, may Allah be pleased with him, refused to repent, so the testimony of Abu Bakrah, may Allah be pleased with him, was henceforth rejected.
Hadith Referenceالسنن المأثورة / باب تفسير الفرعة والعتيرة / 410
Hadith Takhrijالسنن الكبرى للبيهقي: 152/10 ، مصنف عبدالرزاق، رقم الحديث: 13564 ۔