Narrated by:Abu Sa'eed that
It was narrated from Abu Sa'eed that:The Messenger of Allah said: "If you see a man frequenting the mosques, then bear witness to his faith. Allah says: 'The mosques of Allah shall be maintained only by those who believe in Allah and the Last Day. [At-Taubah: 18]'"
حَدَّثَنَا أَبُو كُرَيْبٍ، حَدَّثَنَا رِشْدِينُ بْنُ سَعْدٍ، عَنْ عَمْرِو بْنِ الْحَارِثِ، عَنْ دَرَّاجٍ، عَنْ أَبِي الْهَيْثَمِ، عَنْ أَبِي سَعِيدٍ، عَنْ رَسُولِ اللَّهِ ـ صلى الله عليه وسلم ـ قَالَ " إِذَا رَأَيْتُمُ الرَّجُلَ يَعْتَادُ الْمَسَاجِدَ فَاشْهَدُوا لَهُ بِالإِيمَانِ قَالَ اللَّهُ تَعَالَى {إِنَّمَا يَعْمُرُ مَسَاجِدَ اللَّهِ مَنْ آمَنَ بِاللَّهِ} الآيَةَ .
IbnMaja
The Book On The Mosques And The Congregations • Hadith 802