What to say upon entering a mosque

 247. Abu Hurairah (Or: Abu Usaid) narrated that the Messenger of Allah salla alayhi wa sallam said: ´´When one of you enters a mosque, let him say: ´O Allah! open for me the door of Your mercy.´ And when he steps out, let him say: ´O Allah! I ask you of Your bounty.´´´