Musannaf Ibn Abi Shayba 21:732

'Abbad ibn al-'Awwam narrated to us, from Hajjaj, from 'Umayr ibn Sa'id, that 'Ali performed four takbirs over Yazid ibn al-Mukaffaf. Then he stood over the grave and said: "O Allah, [he is] Your servant and the son of Your servant. He has descended upon You today, and You are the best of those to be descended upon. O Allah, expand his entrance for him and forgive his sin, for we do not know anything but good [about him], and You are more knowing of him than we are."