I heard the Prophet ﷺ say at Nabaa, or at Nabawa (Nafi was uncertain) near Taif, while addressing the people, "People, you are about to come to know the people of Paradise from the people of the Fire," or he said, "the best of you from the worst of you."A man from among the people asked, "By what means, Messenger of Allah?"He replied, "By praise and by blame. You are Allah's witnesses over one another."
حدثنا عبد الملك بن عمرو وسريج المعنى قالا حدثنا نافع بن عمر عن أمية بن صفوان عن أبي بكر بن أبي زهير قال أبي كلاهما قال
سمعت النبي ﷺ يقول بالنباءة أو بالنباوة شك نافع من الطائف وهو يقول يا أيها الناس إنكم توشكون أن تعرفوا أهل الجنة من أهل النار أو قال خياركم من شراركم قال فقال رجل من الناس بم يا رسول الله قال بالثناء السيئ والثناء الحسن وأنتم شهداء الله بعضكم على بعض
Its isnad is sahih. Nafi bin Umar Makki Jumahi is trustworthy and firm, and Safwan bin Umaya bin Abdullah bin Safwan bin Umaya Makki Jumahi, his hadith was accepted. Abu Bakr bin Abu Zuhayr was deemed trustworthy by Ibn Hibban 5/62, while Bukhari passed over him in silence in al-Kuna 9/10, as did Ibn Abu Hatim 9/338.The hadith was narrated by Ibn Majah 2/1411, number (4221), in the chapter on Zuhd, on good praise, and he said in al-Zawaid, sahih.