Sunan an-Nasa'i, Book 21, Hadith 253 (In-Book) ⓘ
It was narrated that Ibn ' Abbas said: "The Messenger of Allah passed by two graves and said: "They are being punished but they are not being punished for anything that was difficult to avoid. One of them used not to take care to avoid getting urine on his body or clothes, and the other used to walk about spreading gossip.' Then he took a fresh palm stalk and broke it in half, and planted one half on each grave. They said: 'O Messenger of Allah, why did not do that?' He said: 'May it be reduced for them so long as this does not dry out."'
أَخْبَرَنَا هَنَّادُ بْنُ السَّرِيِّ، فِي حَدِيثِهِ عَنْ أَبِي مُعَاوِيَةَ، عَنِ الأَعْمَشِ، عَنْ مُجَاهِدٍ، عَنْ طَاوُسٍ، عَنِ ابْنِ عَبَّاسٍ، قَالَ مَرَّ رَسُولُ اللَّهِ صلى الله عليه وسلم بِقَبْرَيْنِ فَقَالَ " إِنَّهُمَا لَيُعَذَّبَانِ وَمَا يُعَذَّبَانِ فِي كَبِيرٍ أَمَّا أَحَدُهُمَا فَكَانَ لاَ يَسْتَبْرِئُ مِنْ بَوْلِهِ وَأَمَّا الآخَرُ فَكَانَ يَمْشِي بِالنَّمِيمَةِ " . ثُمَّ أَخَذَ جَرِيدَةً رَطْبَةً فَشَقَّهَا نِصْفَيْنِ ثُمَّ غَرَزَ فِي كُلِّ قَبْرٍ وَاحِدَةً فَقَالُوا يَا رَسُولَ اللَّهِ لِمَ صَنَعْتَ هَذَا فَقَالَ " لَعَلَّهُمَا أَنْ يُخَفَّفَ عَنْهُمَا مَا لَمْ يَيْبَسَا " .
also referenced under: Hadith 2069 (Reference) & Volume 3, Book 21, Hadith 2071 (DarusSalam)