Once the Prophet, while passing through one of the graveyards of Medina or Mecca heard the voices
of two persons who were being tortured in their graves. The Prophet (ﷺ) said, "These two persons are
being tortured not for a major sin (to avoid)." The Prophet (ﷺ) then added, "Yes! (they are being tortured
for a major sin). Indeed, one of them never saved himself from being soiled with his urine while the
other used to go about with calumnies (to make enmity between friends). The Prophet (ﷺ) then asked for a
green leaf of a date-palm tree, broke it into two pieces and put one on each grave. On being asked why
he had done so, he replied, "I hope that their torture might be lessened, till these get dried."
Sahih al-Bukhari Book 4, Hadith 82