Sunan Abi Dawud 668
سنن أبي داود#668Sahihحَدَّثَنَا أَبُو الْوَلِيدِ الطَّيَالِسِيُّ، وَسُلَيْمَانُ بْنُ حَرْبٍ، قَالاَ حَدَّثَنَا شُعْبَةُ، عَنْ قَتَادَةَ، عَنْ أَنَسٍ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " سَوُّوا صُفُوفَكُمْ فَإِنَّ تَسْوِيَةَ الصَّفِّ مِنْ تَمَامِ الصَّلاَةِ " .
Anas reported the Messenger of Allah (ﷺ) as saying :Straighten your rows for the straightening of the rows is part of perfecting the prayer
Scholarly Authentication
The label above is the grade most of these scholars gave, each scholar counted once — 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. When they judged only its chain of narrators (“Isnaad”), the label says “Sound chain”. Each scholar's own wording:
Our source also lists this ruling under Muhammad Muhyi Al-Din Abdul Hamid, the editor of the printed edition it was taken from. It is al-Albani's ruling printed again, so it is counted once.
In-book reference: 2:278