Narrator:An-Nu‘mān ibn Bashīr
حَدَّثَنَا يَحْيَى بْنُ يَحْيَى، أَخْبَرَنَا أَبُو خَيْثَمَةَ، عَنْ سِمَاكِ بْنِ حَرْبٍ، قَالَ سَمِعْتُ النُّعْمَانَ بْنَ بَشِيرٍ، يَقُولُ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم يُسَوِّي صُفُوفَنَا حَتَّى كَأَنَّمَا يُسَوِّي بِهَا الْقِدَاحَ حَتَّى رَأَى أَنَّا قَدْ عَقَلْنَا عَنْهُ ثُمَّ خَرَجَ يَوْمًا فَقَامَ حَتَّى كَادَ يُكَبِّرُ فَرَأَى رَجُلاً بَادِيًا صَدْرُهُ مِنَ الصَّفِّ فَقَالَ " عِبَادَ اللَّهِ
لَتُسَوُّنَّ صُفُوفَكُمْ أَوْ لَيُخَالِفَنَّ اللَّهُ بَيْنَ وُجُوهِكُمْ "
An-Nu‘mān ibn Bashīr (may Allah be pleased with him) reported that the Prophet (may Allah's peace and blessings be upon him) said: "Straighten your rows or Allah will cause dissension amongst you.''
In another narration: "The Messenger of Allah (may Allah's peace and blessings be upon him) used to straighten our rows, as if he was straightening arrows, until he saw that we had learned it from him. One day he came out, stood for prayer and was about to say 'Allah Akbar' (to start the prayer) when he saw a man whose chest was bulging out from the row. So he said: 'Slaves of Allah, either you straighten your rows or Allah will cause dissension amongst you.'"
Reported by Muslim (No. 436b, 436a, 436c), Al-Bukhari (No. 717), Abu Dawud (No. 662, 663), At-Tirmidhi (No. 227), An-Nasa’i (No. 810), Ibn Majah (No. 994) and Ahmad (No. 17663, 17674, 17700, 17703, 17713).