Musnad Ahmad 32:1096

'Abd al-Razzaq narrated to us, Ma'mar narrated to us, from Thabit, from Anas, who said: A funeral procession passed by the Messenger of Allah, peace and blessings of Allah be upon him, and he said: "Praise it." They said: "As far as we know, he used to love Allah and His Messenger," and they praised him with good. He said: "It has become incumbent." Then another funeral procession passed by him, and he said: "Praise it." They said: "He was a wretched man regarding the religion of Allah." He said: "It has become incumbent. You are the witnesses of Allah upon the earth."