Sahih al-Bukhari · Hadith 3096

One-fifth of Booty to the Cause of Allah (Khumus)

Narrated Abu Huraira: Allah's Messenger (ﷺ) said, "My heirs should not take even a single Dinar (i.e. anything from my property), and whatever I leave, excluding the expenditure of my wives and my laborers, will be Sadaqa (i.e. be used for charity)