Sayyiduna Uqbah bin Amr (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) used to hold our shoulders while we were standing in prayer and would say: "Stand in straight rows and do not differ in the rows (do not stand ahead or behind), for then your hearts will differ."
Hadith Referenceالمنتقى ابن الجارود / كتاب الصلاة / 315
Hadith Gradingغلام مصطفےٰ ظهير امن پوري:صحيح
Hadith Takhrijاز غلام مصطفےٰ ظهير امن پوري:«صحيح مسلم : 432»