Hadith 2:277
Sahih (Al-Albani)
Narrated Anas ibn Malik:
The Prophet (ﷺ) said: Stand close together in your rows, bring them near one another, and stand neck to neck, for by Him in Whose hand my soul is, I see the devil coming in through openings in the row just like a small black sheep.
حَدَّثَنَا مُسْلِمُ بْنُ إِبْرَاهِيمَ، حَدَّثَنَا أَبَانُ، عَنْ قَتَادَةَ، عَنْ أَنَسِ بْنِ مَالِكٍ، عَنْ رَسُولِ اللَّهِ صلى الله عليه وسلم قَالَ " رُصُّوا صُفُوفَكُمْ وَقَارِبُوا بَيْنَهَا وَحَاذُوا بِالأَعْنَاقِ فَوَالَّذِي نَفْسِي بِيَدِهِ إِنِّي لأَرَى الشَّيْطَانَ يَدْخُلُ مِنْ خَلَلِ الصَّفِّ كَأَنَّهَا الْحَذَفُ "
Original Reference: Sunan Abi Dawud 667