question #2 Sahih Muslim 713a, Book 6, Hadith 82 : What is the recommended prayer to say upon leaving a mosque?

When any one of you enters the mosque, he should say:” O Allah! open for me the doors of Thy mercy” ; and when he steps out he should say: ‘O Allah! I beg of Thee Thy Grace.” (Imam Muslim said: I heard Yahya saying: I transcribed this hadith from the compilation of Sulaiman b. Bilal.)