عَنْ أَبِي هُرَيْرَةَ رَضِيَ اللَّهُ عَنْهُ قَالَ: سَمِعْتُ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ يَقُولُ: ((مَنْ سَمِعَ رَجُلًا يَنْشُدُ فِي الْمَسْجِدِ ضَالَّةً فَلْيَقُلْ لَهُ: لَا أَدَّاهَا اللَّهُ إِلَيْكَ، فَإِنَّ الْمَسَاجِدَ لَمْ تُبْنَ لِهَٰذَا))
It is narrated from Sayyiduna Abu Hurairah, may Allah be pleased with him, that the Messenger of Allah, peace and blessings be upon him, said: Whoever hears a man announcing a lost item in the mosque, let him say to him: May Allah not return it to you, for the mosques were not built for this purpose.