بُلُوغُ الْمَرَامِ
Bulugh al-Maram 415
The Book of Prayer
وَعَنْ أَنَسٍ, عَنْ اَلنَّبِيِّ - صلى الله عليه وسلم -قَالَ: { رُصُّوا صُفُوفَكُمْ, وَقَارِبُوا بَيْنَهَا, وَحَاذُوا بِالْأَعْنَاقِ. } رَوَاهُ أَبُو دَاوُدَ, وَالنَّسَائِيُّ, وَصَحَّحَهُ اِبْنُ حِبَّانَ . [1] .
Narrated Anas (RA): Allah's Messenger (ﷺ) said: "Stand close together in your rows, bring them (the rows) near one another, and stand neck to neck (in straight lines)." [Reported by Abu Dawud and an-Nasa'i. And Ibn Hibban graded it Sahih (authentic)].
Sunnah.com reference: Book 2, Hadith 320