The Book of Prayer
Bulugh al-Maram #304
كتاب الصلاة
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 مُسْلِمٌ
Narrated:
Allah's Messenger (ﷺ) 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.”
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 مُسْلِمٌ
Allah's Messenger (ﷺ) 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."
— Bulugh al-Maram, Hadith 304