(36) باب الْقَوْلِ عِنْدَ دُخُولِ الْمَسْجِدِ وَعِنْدَ الْخُرُوجِ مِنْهُ
It was narrated that 'Abdul-Malik bin Sa'eed said:
"I heard Abu Humaid and Abu Usaid say: 'The Messenger of Allah (ﷺ) said: "When any one of you enters the Masjid, let him say: 'Allahumma aftahli abwaba rahmatik (O Allah, open to me the gates of your mercy). And when he leaves let him say: Allahumma inni as'aluka min fadlik (O Allah, I ask You of Your bounty).'" (RU)
Reference (RU): Sunan an-Nasa'i 729 (RU)
In-book reference (RU): Book 8, Hadith 42 (RU)
English translation (RU): Vol. 1, Book 8, Hadith 730 (RU)