Sahih al-Bukhari · Hadith 3104

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

Narrated `Abdullah: The Prophet (ﷺ) stood up and delivered a sermon, and pointing to `Aisha's house (i.e. eastwards), he said thrice, "Affliction (will appear from) here," and, "from where the side of the Satan's head comes out (i.e. from the East)