(20) باب الْكَلاَمِ فِي الصَّلاَةِ
It was narrated from Abu Hurairah that:
A Bedouin entered the masjid and prayed two rak'ahs, then he said: "O Allah, have mercy on me and on Muhammad and do not have mercy on anyone else." The Messenger of Allah (ﷺ) said: "You have limited something vast."
Reference: Sunan an-Nasa'i 1217
In-book reference: Book 13, Hadith 39
English translation: Vol. 2, Book 13, Hadith 1218