The Prophet ﷺ had his grave dug with a side niche, bricks were set up over it, and his grave was raised about a hand-span above the ground.
أن النبي ﷺ حد، ونصب عليه اللبن نصبا، ورفع قبره من الأرض نحوا من شبر.
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Ibn Hibban (6635) and Bayhaqi (3/410) both narrated it through Abu Kamil Jahdari, who said, Fudayl bin Sulayman narrated to us, who said, Jafar bin Muhammad narrated to us, from his father, from Jabir bin Abdullah, and he mentioned it. Its isnad is sahih.It is understood from this that it is recommended to raise the grave a hand span above the ground so that it can be distinguished, and thus be protected from being disrespected or treated with disregard.