chapter on the Prophet's disapproval of seeking a lost thing inside the Masjid

Abu Hurayrah (May Allah be pleased with him) said: The Messenger of Allah (peace be upon him) said: "If anyone hears a man inquiring in the mosque about something he has lost, he should say: `La Raddaha Allahu `Alayka (May Allah not restore it to you),' for mosques are not built for this purpose." [Reported by Muslim in his Sahih]

Buraydah (May Allah be pleased with him) said: A man announced (the loss of his camel) in the mosque, uttering these words: "Has any one seen my red camel?'' Upon this the Messenger of Allah (peace be upon him) said: "May it not be restored to you! The mosques are built for what they are meant to be (i.e., prayer, remembrance of Allah, acquiring knowledge, etc.)." [Reported by Muslim in his Sahih]

Abu Hurayrah (May Allah be pleased with him) said: The Messenger of Allah said: "When you see someone buying or selling in the mosque, say to him: `La Arbaha-Allahu Tijarataka (May Allah not make your bargain profitable)!' When you see someone announcing something lost in it, say: `May Allah not restore it to you!''' [Reported by At-Tirmidhy in his Sunan and said: It is a good Hadith].