Sahih al-Bukhari 23:130
Narrated Ibn `Abbas:
The Prophet (ﷺ) once passed by two graves and said, "They (the deceased persons in those graves) are being tortured not for a great thing to avoid." And then added, "Yes, (they are being punished for a big sin), for one of them used to go about with calumnies while the other never saved himself from being soiled with his urine." (Ibn `Abbas added): Then he took a green leaf of a date-palm) and split it into two pieces and fixed one piece on each grave and said, "May their punishment be abated till these (two pieces) get dry."
Reference
Sahih al-Bukhari 23:130
In-book reference
Book 23, Hadith 130
Arabic Text
حَدَّثَنَا قُتَيْبَةُ، حَدَّثَنَا جَرِيرٌ، عَنِ الأَعْمَشِ، عَنْ مُجَاهِدٍ، عَنْ طَاوُسٍ، قَالَ ابْنُ عَبَّاسٍ ـ رضى الله عنهما ـ مَرَّ النَّبِيُّ صلى الله عليه وسلم عَلَى قَبْرَيْنِ فَقَالَ " إِنَّهُمَا لَيُعَذَّبَانِ، وَمَا يُعَذَّبَانِ مِنْ كَبِيرٍ ـ ثُمَّ قَالَ ـ بَلَى أَمَّا أَحَدُهُمَا فَكَانَ يَسْعَى بِالنَّمِيمَةِ، وَأَمَّا أَحَدُهُمَا فَكَانَ لاَ يَسْتَتِرُ مِنْ بَوْلِهِ ". قَالَ ثُمَّ أَخَذَ عُودًا رَطْبًا فَكَسَرَهُ بِاثْنَتَيْنِ ثُمَّ غَرَزَ كُلَّ وَاحِدٍ مِنْهُمَا عَلَى قَبْرٍ، ثُمَّ قَالَ " لَعَلَّهُ يُخَفَّفُ عَنْهُمَا مَا لَمْ يَيْبَسَا ".