Thumamah bin Shufayy says: We set out on a campaign in the time of Mu'awiyah (may Allah be pleased with him) towards these lands, and Fadalah bin Ubayd (may Allah be pleased with him) was in command over us. A cousin of mine, called Nafi' bin Abd, died. He says: Fadalah (may Allah be pleased with him) stood at his grave, and when we had buried him he said: Lighten the soil over him, for the Messenger of Allah (peace and blessings be upon him) "used to order us to level the graves."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجنائز / 6738