question #1 Sahih Muslim 968, Book 11, Hadith 119 : What is the significance of leveling a grave in Islamic burial practices?

When we were with Fadala b. ‘Ubaid in the country of the Romans at a place (known as) Rudis, a friend of ours died. Fadala b. ‘Ubaid ordered to prepare a grave for him and then it was levelled; and then he said: I heard the Messenger of Allah (ﷺ) commanding (us) to level the grave.