A'ishah (RAA) narrated that the Messenger of Allah (ﷺ) said:
"Avoid reviling the dead, they have already seen the result of (the deeds) that they forwarded before them." Related by Al-Bukhari. (PT)
English reference (PT): Book 16, Hadith 1547 (PT)
Arabic reference (PT): Book 16, Hadith 1504 (PT)