Hadith 15439
Abu Bakr bin Abi Zuhair narrates from his father: I heard the Prophet (peace be upon him) in the time of Prophethood in Taif saying, "O people, soon you will be able to distinguish between the people of Paradise and the people of Hell, or between the good and the bad." A man asked, "O Messenger of Allah! How is that?" The Prophet (peace be upon him) replied, "Through the good and bad praise of people, because you are Allah's witnesses over one another on earth."