حَدَّثَنَا مُوسَى بْنُ إِسْمَاعِيلَ، حَدَّثَنَا حَمَّادٌ، عَنْ سِمَاكِ بْنِ حَرْبٍ، قَالَ سَمِعْتُ النُّعْمَانَ بْنَ بَشِيرٍ، يَقُولُ كَانَ النَّبِيُّ صلى الله عليه وسلم يُسَوِّينَا فِي الصُّفُوفِ كَمَا يُقَوَّمُ الْقِدْحُ حَتَّى إِذَا ظَنَّ أَنْ قَدْ أَخَذْنَا ذَلِكَ عَنْهُ وَفَقِهْنَا أَقْبَلَ ذَاتَ يَوْمٍ بِوَجْهِهِ إِذَا رَجُلٌ مُنْتَبِذٌ بِصَدْرِهِ فَقَالَ ‏"‏لَتُسَوُّنَّ صُفُوفَكُمْ أَوْ لَيُخَالِفَنَّ اللَّهُ بَيْنَ وُجُوهِكُمْ ‏"

Al-Nu’man b. Bashir said

The Prophet (ﷺ) used to straighten us in the rows as the arrow is straightened, until he thought that we had understood that from him. Then, one day, he came out and faced us, and when a man was protruding with his chest [from the row], he said: "You must straighten your rows, or Allah will certainly cause disagreement between your faces."