Bulugh al-Maram
Sa'd bin Abi Wqqas (RAA) said (during his death illness) ‘Make a lahd for me and cover it with un-burnt bricks, as you did with the grave of the Prophet (ﷺ).’ Related by Muslim.
وَعَنْ سَعْدِ بْنِ أَبِي وَقَّاصٍ - رضى الله عنه - قَالَ: { أَلْحَدُو ا 1 لِي لَحْدًا, وَانْصِبُوا عَلَى اللَّبِنِ نُصْبًا, كَمَا صُنِعَ بِرَسُولِ اللَّهِ - صلى الله عليه وسلم -. } رَوَاهُ مُسْلِم ٌ 2 .
Reference