لَا تَسُبُّوا الْأَمْوَاتَ فَإِنَّهُمْ قَدْ أَفْضَوْا إِلَى مَا قَدَّمُوا
Do not revile the dead, for they have reached the consequences of what they sent ahead.
Source: البخاري
لَا تَسُبُّوا is a plural prohibition: “do not revile.” الْأَمْوَاتَ means “those who have died,” أَفْضَوْا إِلَى means “have reached,” and مَا قَدَّمُوا refers to their earlier deeds and their consequences.
Insulting a deceased person does not reform them but can needlessly hurt survivors. The instruction promotes restraint and dignity in speech. It should not be confused with truthful, necessary examination of past actions for justice, protection, or reliable historical learning.