Sunan an-Nasa'i 816
سنن النسائي#816Sahihأَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا الْفُضَيْلُ بْنُ عِيَاضٍ، عَنِ الأَعْمَشِ، عَنِ الْمُسَيَّبِ بْنِ رَافِعٍ، عَنْ تَمِيمِ بْنِ طَرَفَةَ، عَنْ جَابِرِ بْنِ سَمُرَةَ، قَالَ خَرَجَ إِلَيْنَا رَسُولُ اللَّهِ صلى الله عليه وسلم فَقَالَ " أَلاَ تَصُفُّونَ كَمَا تَصُفُّ الْمَلاَئِكَةُ عِنْدَ رَبِّهِمْ " . قَالُوا وَكَيْفَ تَصُفُّ الْمَلاَئِكَةُ عِنْدَ رَبِّهِمْ قَالَ " يُتِمُّونَ الصَّفَّ الأَوَّلَ ثُمَّ يَتَرَاصُّونَ فِي الصَّفِّ " .
It was narrated that Jabir bin Samurah said:"The Messenger of Allah (ﷺ) came out to us and said:'Will you not form rows as the angels form rows before their Lord? They said: 'How do the angels form rows before their lord? He said: 'They complete the first row and fill the gaps in the rows
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
In-book reference: 10:40