صحيح البخاري Sahih Bukhari كتاب الجنائز The Book of Al-Janaiz (Funerals)
بَابُ الصَّلاَةِ عَلَى الْقَبْرِ بَعْدَ مَا يُدْفَنُ:

(66) Chapter. To offer the (funeral) Salat (prayer) on the grave after the burial of the deceased.

2 hadith
Hadith 1336
حَدَّثَنَا حَجَّاجُ بْنُ مِنْهَالٍ ، حَدَّثَنَا شُعْبَةُ , قَالَ : حَدَّثَنِي سُلَيْمَانُ الشَّيْبَانِيُّ , قَالَ : سَمِعْتُ الشَّعْبِيَّ , قَالَ : " أَخْبَرَنِي مَنْ مَرَّ مَعَ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ عَلَى قَبْرٍ مَنْبُوذٍ فَأَمَّهُمْ وَصَلَّوْا خَلْفَهُ " ، قُلْتُ : مَنْ حَدَّثَكَ هَذَا يَا أَبَا عَمْرٍو ؟ قَالَ : ابْنُ عَبَّاسٍ رَضِيَ اللَّهُ عَنْهُمَا .
Narrated Sulaiman Ash-Shaibani: I heard Ash-Shu`bi saying, "I was told by a man who had passed with the Prophet (p.b.u.h) by a grave that was separate from the other graves that he (the Prophet ) led them in the prayer and they prayed behind him." I said, "O Abu `Amr! Who narrated that to you?" He replied, "Ibn `Abbas."
Hadith Reference Sahih Bukhari / The Book of Al-Janaiz (Funerals) / Hadith: 1336
Hadith Grading محدثین: أحاديث صحيح البخاريّ كلّها صحيحة
Hadith 1337
حَدَّثَنَا مُحَمَّدُ بْنُ الْفَضْلِ ، حَدَّثَنَا حَمَّادُ بْنُ زَيْدٍ ، عَنْ ثَابِتٍ ، عَنْ أَبِي رَافِعٍ ، عَنْ أَبِي هُرَيْرَةَ رَضِيَ اللَّهُ عَنْهُ ، " أَنَّ أَسْوَدَ رَجُلًا , أَوِ امْرَأَةً , كَانَ يَقُمُّ الْمَسْجِدَ فَمَاتَ , وَلَمْ يَعْلَمْ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ بِمَوْتِهِ ، فَذَكَرَهُ ذَاتَ يَوْمٍ , فَقَالَ : مَا فَعَلَ ذَلِكَ الْإِنْسَانُ ؟ , قَالُوا : مَاتَ يَا رَسُولَ اللَّهِ ، قَالَ : أَفَلَا آذَنْتُمُونِي ، فَقَالُوا : إِنَّهُ كَانَ كَذَا , وَكَذَا قِصَّتُهُ ، قَالَ : فَحَقَرُوا شَأْنَهُ ، قَالَ فَدُلُّونِي عَلَى قَبْرِهِ فَأَتَى قَبْرَهُ فَصَلَّى عَلَيْهِ " .
Narrated Abu Huraira: A black person, a male or a female used to clean the Mosque and then died. The Prophet (p.b.u.h) did not know about it . One day the Prophet remembered him and said, "What happened to that person?" The people replied, "O Allah's Apostle! He died." He said, "Why did you not inform me?" They said, "His story was so and so (i.e. regarded him as insignificant)." He said, "Show me his grave." He then went to his grave and offered the funeral prayer.
Hadith Reference Sahih Bukhari / The Book of Al-Janaiz (Funerals) / Hadith: 1337
Hadith Grading محدثین: أحاديث صحيح البخاريّ كلّها صحيحة