Bulugh al-Maram 2 The Book of Prayer كتاب الصلاة 125

وَعَنْهُ قَالَ : قَالَ رَسُولُ اَللَّهِ – صلى الله عليه وسلم -{ مَنْ سَمِعَ رَجُلاً يَنْشُدُ ضَالَّةً فِي اَلْمَسْجِدِ فَلْيَقُلْ : لَا رَدَّهَا اَللَّهُ عَلَيْكَ , فَإِنَّ اَلْمَسَاجِدَ لَمْ تُبْنَ لِهَذَا } رَوَاهُ مُسْلِم ٌ 1 1 – صحيح . رواه مسلم (568) .

Narrated [Abu Hurairah (RA)]: Allah’s Messenger (صلى الله عليه وسلم) said: “Whoever hears a man crying out in the mosque about something he has lost, he should say, ‘May Allah not restore it to you’, for the mosques were not built for this.” [Reported by Muslim].