Musnad Abu Ya'la al-Mawsili 129:43

A funeral passed by the Messenger of Allah, may Allah bless him and grant him peace, and they praised it with good, until the tongues followed one another with good. The Messenger of Allah, may Allah bless him and grant him peace, said, "It has become incumbent." Then another passed by him, and they praised it with evil. The Messenger of Allah, may Allah bless him and grant him peace, said, "It has become incumbent." Then he said, "You are the witnesses of Allah upon the earth."