Complete the front row first, then the one following it. If there is any deficiency (in the rows), let it be in the last row

The Messenger of Allah (ﷺ) said, "Fill (complete) the first row, then the one next to it; and if there is any deficiency (incompleteness), it should be in the last row." [Abu Dawud].

"‏أتموا الصف المقدم، ثم الذي يليه، فما كان من نقص فليكن في الصف المؤخر‏"

He reported God’s Messenger as saying, "Complete the front row, then the one that comes next, and if there is any incompleteness let it be in the last row.” Abu Dawud transmitted it.

وَعَنْهُ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «أَتِمُّوا الصَّفَّ الْمُقَدَّمَ ثُمَّ الَّذِي يَلِيهِ فَمَا كَانَ مِنْ نَقْصٍ فَلْيَكُنْ فِي الصَّفّ الْمُؤخر» . رَوَاهُ أَبُو دَاوُد

The Messenger of Allah (ﷺ) used to gently pat our shoulders when we were standing in rows at the time of Salat and say, "Keep (the rows) straight; do not differ from each other lest your hearts should suffer from discord. Let those of you who are mature and prudent be nearer to me, and then those…

"‏استووا ولا تختلفوا فتختلف قلوبكم، ليلني منكم أولو الأحلام والنهى، ثم الذين يلونهم ثم الذين يلونهم‏"

Narrated by Abu Mas‘ūd al-Badrī + 10 other versions

The Messenger of Allah (ﷺ) said, "Keep your rows straight (during Salat in congregation), for keeping the rows straight is part of the perfection of Salat." [Al-Bukhari and Muslim].

وعن أنس، رضي الله عنه قال‏:‏ قال رسول الله صلى الله عليه وسلم‏:‏ ‏"‏سووا صفوفكم، فإن تسوية الصف من تمام الصلاة‏"‏‏.‏ ‏(‏‏(‏متفق عليه‏)‏‏)‏ وفي رواية البخاري‏:‏ ‏"‏فإن تسوية الصفوف من إقامة الصلاة‏"‏‏.‏

+ 12 other versions

I heard the Messenger of Allah (ﷺ) saying, "Straighten your rows; otherwise, Allah will create dissension among you." [Al- Bukhari and Muslim]. The narration in Muslim is: An-Nu'man bin Bashir (May Allah be pleased with them) said: The Messenger of Allah (ﷺ) directed us to keep our rows as straight…

وعن النعمان بن بشير رضي الله عنهما، قال‏:‏ سمعت رسول الله صلى الله عليه وسلم يقول‏:‏ ‏"‏لتسون صفوفكم، أو ليخالفن الله بين وجوهكم‏"‏ ‏(‏‏(‏متفق عليه‏)‏‏)‏ وفي رواية لمسلم‏:‏ أن رسول الله صلى الله عليه وسلم كان يسوي…

Narrated by An-Nu‘mān ibn Bashīr + 16 other versions

The Messenger of Allah (ﷺ) used to pass between the rows from one end to the other, touching our chest and shoulders (i.e., arranging the rows) in line and saying, "Do not be out of line; otherwise your hearts will be in disagreement". He would add, "Allah and His angels invoke blessings upon the…

وعن البراء بن عازب رضي الله عنهما، قال كان رسول الله صلى الله عليه وسلم يتخلل من ناحية إلى ناحية، يمسح صدورنا ومناكبنا ويقول،‏:‏ ‏"‏لا تختلفوا فتختلف قلوبكم‏"‏ وكان يقول‏:‏ ‏"‏إن الله وملائكته يصلون على الصفوف الأُول‏"‏…

Narrated by Al-Barā' ibn ‘Āzib + 8 other versions

Messenger of Allah (ﷺ) said, "Let those be nearest to me in Salat (prayer) who are mature and possess (religious) knowledge, then those who are nearest to them in these respects". He repeated this three times and then added, "Beware of indulging in the loose talks of the markets (when you are in…

وعن عبد الله بن مسعود رضي الله عنه قال‏:‏ قال رسول الله صلى الله عليه وسلم‏:‏ ‏"‏ليلني منكم أولو الأحلام والنهى، ثم الذين يلونهم‏"‏ ثلاثًا ‏"‏وإياكم وهيشات الأسوق‏"‏ ‏(‏‏(‏رواه مسلم‏)‏‏)‏‏.‏

Narrated by Abdullah ibn Mas‘ūd + 5 other versions

The Messenger of Allah (ﷺ) said, "Let the Imam stand in the middle (so that those praying behind him should be standing both on his right and his left) and close the gaps." [Abu Dawud].

"‏وسطوا الإمام، وسدوا الخلل‏"

Narrated by Abu Hurayrah + 1 other version