Musnad Abu Ya'la al-Mawsili 160:174

Muhammad ibn Ishaq al-Musayyibi narrated to us, Abdullah ibn Nafi’ narrated to us, from Abdullah ibn Umar, from al-Maqburi, from Abu Hurairah, that the Prophet (peace be upon him) passed by a funeral, and they praised it with good. The Prophet (peace be upon him) said, "It has become incumbent." Then another funeral passed by him, and they praised it with evil. The Prophet (peace be upon him) said, "It has become incumbent." Then he said, "You are the witnesses of Allah upon the earth."