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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
ahmad:12572 – Aswad b. ʿĀmir > Jaʿfar / al-Aḥmar > ʿAṭāʾ b. al-Sāʾib > Anas

[Machine] The Messenger of Allah ﷺ said, "Straighten the rows, for verily Shaytan stands in the gaps."  

أحمد:١٢٥٧٢ – حَدَّثَنَا أَسْوَدُ بْنُ عَامِرٍ أَخْبَرَنَا جَعْفَرٌ يَعْنِي الْأَحْمَرَ عَنْعَطَاءِ بْنِ السَّائِبِ عَنْ أَنَسٍ قَالَ

قَالَ رَسُولُ اللهِ ﷺ رَاصُّوا الصُّفُوفَ فَإِنَّ الشَّيْطَانَ يَقُومُ فِي الْخَلَلِ  

See similar narrations below:

Collected by Suyūṭī