ENOfficial
Abu Rafi‘ said that God's messenger lowered Sa‘d and sprinkled water over his grave. Ibn Majah transmitted it.
Source: sunnah.com
Other translations
Arabic
وَعَنْ أَبِي رَافِعٍ قَالَ: سَلَّ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ سَعْدًا وَرَشَّ عَلَى قَبره مَاء. رَوَاهُ ابْن مَاجَه
sunnah.com