صَحِيحُ مُسْلِمٍ
Sahih Muslim 568 a
The Book of Mosques and Places of Prayer
The prohibition of making lost property announcements in the masjid, and what should be said by one who hears a person making such an announcement
حَدَّثَنَا أَبُو الطَّاهِرِ، أَحْمَدُ بْنُ عَمْرٍو حَدَّثَنَا ابْنُ وَهْبٍ، عَنْ حَيْوَةَ، عَنْ مُحَمَّدِ بْنِ عَبْدِ الرَّحْمَنِ، عَنْ أَبِي عَبْدِ اللَّهِ، مَوْلَى شَدَّادِ بْنِ الْهَادِ أَنَّهُ سَمِعَ أَبَا هُرَيْرَةَ، يَقُولُ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم مَنْ سَمِعَ رَجُلاً يَنْشُدُ ضَالَّةً فِي الْمَسْجِدِ فَلْيَقُلْ لاَ رَدَّهَا اللَّهُ عَلَيْكَ فَإِنَّ الْمَسَاجِدَ لَمْ تُبْنَ لِهَذَا .
Abu Huraira reported: The Messenger of Allah (ﷺ) said: If anyone 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.
Sahih Muslim, 568 aSahihصحيح