They are being tormented, but they are not tormented for a major sin. One of them would not save himself from being soiled with his urine, while the other used to walk about spreading malicious gossip

عَنِ ابْنِ عَبَّاسٍ رضي الله عنهما قَالَ: مَرَّ النَّبِيُّ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ بِقَبْرَيْنِ، فَقَالَ: «إِنَّهُمَا لَيُعَذَّبَانِ، وَمَا يُعَذَّبَانِ فِي كَبِيرٍ، أَمَّا أَحَدُهُمَا فَكَانَ لاَ يَسْتَتِرُ مِنَ البَوْلِ، وَأَمَّا الآخَرُ فَكَانَ يَمْشِي بِالنَّمِيمَةِ» ثُمَّ أَخَذَ جَرِيدَةً رَطْبَةً، فَشَقَّهَا نِصْفَيْنِ، فَغَرَزَ فِي كُلِّ قَبْرٍ وَاحِدَةً، قَالُوا: يَا رَسُولَ اللَّهِ، لِمَ فَعَلْتَ هَذَا؟ قَالَ: «لَعَلَّهُ يُخَفِّفُ عَنْهُمَا مَا لَمْ يَيْبَسَا».

Ibn ‘Abbās (may Allah be pleased with him and his father) reported: The Prophet (may Allah's peace and blessings be upon him) passed by two graves and said: "They are being tormented, but they are not tormented for a major sin. One of them would not save himself from being soiled with his urine, while the other used to walk about spreading malicious gossip." He then took a green leaf of a date palm, split it into two, and planted one on each grave. They said: O Messenger of Allah, why did you do that? He replied: "Their torment might be alleviated until they become dry."

Source · Agreed upon

From the Hadith Encyclopedia (hadeethenc.com).