Hadith 21:214
Sahih (Darussalam)
Thumamah bin Shufa narrated:
"We were with Fadalah bin 'Ubaid in the land of the Romans, and a companion of ours died. Fadalah ordered that his grave be made level, then he said: 'I heard the Messenger of Allah commanding that it be made level."'
أَخْبَرَنَا سُلَيْمَانُ بْنُ دَاوُدَ، قَالَ أَنْبَأَنَا ابْنُ وَهْبٍ، قَالَ أَخْبَرَنِي عَمْرُو بْنُ الْحَارِثِ، أَنَّ ثُمَامَةَ بْنَ شُفَىٍّ، حَدَّثَهُ قَالَ : كُنَّا مَعَ فَضَالَةَ بْنِ عُبَيْدٍ بِأَرْضِ الرُّومِ فَتُوُفِّيَ صَاحِبٌ لَنَا، فَأَمَرَ فَضَالَةُ بِقَبْرِهِ فَسُوِّيَ، ثُمَّ قَالَ : سَمِعْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم يَأْمُرُ بِتَسْوِيَتِهَا
Original Reference: Sunan an-Nasa'i 2030