It was narrated from Abu ‘Abdullah, the freed slave of Shaddad bin Had that: He heard Abu Hurairah say: “I heard the Messenger of Allah say: ‘Whoever hears a man making a lost-and-found announcement in the mosque, let him say: “May Allah not return it to you!” For the mosques were not built for that.'”
Sunan Ibn Majah, Book 4, Hadith 33
