Sunan an-Nasa'i, Volume 3, Book 21, Hadith 1938 (DarusSalam) ⓘ
It was narrated that 'Aishah said: "The Messenger of Allah said: 'Do not verbally abuse the dead, for they have reached the consequences of what they did."'
أَخْبَرَنَا حُمَيْدُ بْنُ مَسْعَدَةَ، عَنْ بِشْرٍ، - وَهُوَ ابْنُ الْمُفَضَّلِ - عَنْ شُعْبَةَ، عَنْ سُلَيْمَانَ الأَعْمَشِ، عَنْ مُجَاهِدٍ، عَنْ عَائِشَةَ، قَالَتْ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " لاَ تَسُبُّوا الأَمْوَاتَ فَإِنَّهُمْ قَدْ أَفْضَوْا إِلَى مَا قَدَّمُوا " .
also referenced under: Hadith 1936 (Reference) & Book 21, Hadith 120 (In-Book)