Musnad Ahmad 1141:1

Yazid ibn Harun narrated to us, Nafi‘ ibn ‘Umar narrated to us, from Umayyah ibn Safwan, from Abu Bakr ibn Abi Zuhayr, from his father, who said: I heard the Messenger of Allah, may Allah bless him and grant him peace, saying in his sermon at al-Nabawah—or al-Banawah—in Ta’if: "It is imminent that you will know the people of Paradise from the people of the Fire," or "your best from your worst." And I do not know it except that he said: "The people of Paradise from the people of the Fire." A speaker from the Muslims said: "By what, O Messenger of Allah?" He said: "By the good praise and the bad praise. You are witnesses, some of you over others."