Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
Qurʾān Bukhārī Muslim Nasāʾī Abū Dāwūd Tirmidhī Ibn Mājah Mālik Aḥmad Dārimī Ḥākim Ibn Ḥibbān Ṭabarānī Nasāʾī's Kubrá Bayhaqī al-Luʾluʾ wa-al-Marjān Ibn Rajab's Fifty Riyāḍ al-Ṣāliḥīn Aḥmad's Zuhd Suyūṭī
hakim:770 – Abū al-ʿAbbās Muḥammad b. Yaʿqūb > Baḥr b. Naṣr > Quriʾ > Ibn WahbAkhbarak ʿAmr b. al-Ḥārith > Abū al-Naḍr al-Faqīh > ʿUthmān b. Saʿīd al-Dārimī > Aṣbagh b. al-Faraj > ʿAbdullāh b. Wahb > ʿAmr b. al-Ḥārith > Darrāj > Abū al-Haytham > Abū Saʿīd al-Khudrī > Qāl Rasūl

[Machine] The Messenger of Allah ﷺ said, "When you see a man frequenting the mosque, bear witness to his faith." Allah, the Exalted, said: "Verily, those who attend to the mosques of Allah are those who believe in Allah and the Last Day." [Surah At-Tawbah: 18] This is a translation for the Egyptians. They did not differ in its accuracy and the truthfulness of its narrators, except that the two authentic scholars did not mention it. However, I have mentioned the statement regarding its authenticity in the previous explanation.  

الحاكم:٧٧٠ – حَدَّثَنَا أَبُو الْعَبَّاسِ مُحَمَّدُ بْنُ يَعْقُوبَ أَنْبَأَ بَحْرُ بْنُ نَصْرٍ قَالَ قُرِئَ عَلَى ابْنِ وَهْبٍ أَخْبَرَكَ عَمْرُو بْنُ الْحَارِثِ وَأَخْبَرَنَا أَبُو النَّضْرِ الْفَقِيهُ ثنا عُثْمَانُ بْنُ سَعِيدٍ الدَّارِمِيُّ ثنا أَصْبَغُ بْنُ الْفَرَجِ أَنْبَأَ عَبْدُ اللَّهِ بْنُ وَهْبٍ أَخْبَرَنِي عَمْرُو بْنُ الْحَارِثِ عَنْ دَرَّاجٍ حَدَّثَهُ عَنْ أَبِي الْهَيْثَمِ عَنْ أَبِي سَعِيدٍ الْخُدْرِيِّ قَالَ

قَالَ رَسُولُ اللَّهِ ﷺ «إِذَا رَأَيْتُمُ الرَّجُلَ يَعْتَادُ الْمَسْجِدَ فَاشْهَدُوا عَلَيْهِ بِالْإِيمَانِ» قَالَ اللَّهُ ﷻ {إِنَّمَا يَعْمُرُ مَسَاجِدَ اللَّهِ مَنْ آمَنَ بِاللَّهِ وَالْيَوْمِ الْآخِرِ} [التوبة 18] «» هَذِهِ تَرْجَمَةٌ لِلْمِصْرِيِّينَ لَمْ يَخْتَلِفُوا فِي صِحَّتِهَا وَصِدْقِ رُوَاتِهَا غَيْرَ أَنَّ شَيْخَيِ الصَّحِيحِ لَمْ يُخَرِّجَاهُ وَقَدْ سُقْتُ الْقَوْلَ فِي صِحَّتِهِ فِيمَا تَقَدَّمَ دراج كثير المناكير  

See similar narrations below:

Collected by Aḥmad, Bayhaqī
ahmad:11651 –

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]'" (Using translation from Ibn Mājah 802)   

أحمد:١١٦٥١ – وَبِهَذَا الْإِسْنَادِ

أَنَّ رَسُولَ اللهِ ﷺ قَالَ إِذَا رَأَيْتُمُ الرَّجُلَ يَعْتَادُ الْمَسْجِدَ فَاشْهَدُوا عَلَيْهِ بِالْإِيمَانِ قَالَ اللهُ ﷻ {إِنَّمَا يَعْمُرُ مَسَاجِدَ اللهِ مَنْ آمَنَ بِاللهِ وَالْيَوْمِ الْآخِرِ}  

bayhaqi:4988 – [Chain 1] Abū ʿAbdullāh al-Ḥāfiẓ > Abū al-ʿAbbās Muḥammad b. Yaʿqūb > Baḥr b. Naṣr > Quriʾ > Ibn WahbAkhbarak ʿAmr b. al-Ḥārith [Chain 2] Abū al-Naḍr al-Faqīh > ʿUthmān b. Saʿīd al-Dārimī > Aṣbagh b. al-Faraj > ʿAbdullāh b. Wahb > ʿAmr b. al-Ḥārith > Darrāj > Abū al-Haytham > Abū Saʿīd al-Khudrī

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]'" (Using translation from Ibn Mājah 802)   

البيهقي:٤٩٨٨ – أَخْبَرَنَا أَبُو عَبْدِ اللهِ الْحَافِظُ ثنا أَبُو الْعَبَّاسِ مُحَمَّدُ بْنُ يَعْقُوبَ ثنا بَحْرُ بْنُ نَصْرٍ قَالَ قُرِئَ عَلَى ابْنِ وَهْبٍ أَخْبَرَكَ عَمْرُو بْنُ الْحَارِثِ ح قَالَ وَأَخْبَرَنَا أَبُو النَّضْرِ الْفَقِيهُ ثنا عُثْمَانُ بْنُ سَعِيدٍ الدَّارِمِيُّ ثنا أَصْبَغُ بْنُ الْفَرَجِ ثنا عَبْدُ اللهِ بْنُ وَهْبٍ أَخْبَرَنِي عَمْرُو بْنُ الْحَارِثِ عَنْ دَرَّاجٍ حَدَّثَهُ عَنْ أَبِي الْهَيْثَمِ عَنْ أَبِي سَعِيدٍ الْخُدْرِيِّ قَالَ

قَالَ رَسُولُ اللهِ ﷺ إِذَا رَأَيْتُمُ الرَّجُلَ يَعْتَادُ الْمَسَاجِدَ فَاشْهَدُوا عَلَيْهِ بِالْإِيمَانِ قَالَ اللهُ ﷻ {إِنَّمَا يَعْمُرُ مَسَاجِدَ اللهِ مَنْ آمَنَ بِاللهِ وَالْيَوْمِ الْآخِرِ} [التوبة 18]