Chapter 20: The Book of Qiyam Al-Lail (The Night Prayer) and Voluntary Prayers During the Day
It was narrated from Sa' d bin Ishaq bin Ka' b bin Ujrah, from his father, that: His grandfather said: "The Messenger of Allah (ﷺ) prayed Maghrib in the masjid of Banu 'Abdul-Ashhal, and when he finished praying some people stood up and offered Nafl prayers. The Prophet (ﷺ) said: 'You should offer this prayer in your houses.'"
Sunan an-Nasa'i 1600