Leaving the Masjid
اللَّهُمَّ إِنِّي أَسْأَلُكَ مِنْ فَضْلِكَ
Allahumma inni as'aluka min fadlik.
O Allah, I ask You from Your bounty.
What it means
Going in you ask for mercy; going out you ask for provision, because you are returning to work, trade and the needs of the world. The pairing teaches that both halves of life are asked for from the same door.
When and how
Step out with your left foot first and say it once.
Its virtue
Taught by the Prophet ﷺ as the words to say when leaving a masjid, reported in Sahih Muslim 713.
Source
Muslim 713sahih