With this hadith, he said that whenever the Messenger of Allah ﷺ stood up for prayer, he would take hold of it with his right hand, then turn and say, "Straighten yourselves, align your rows." Then he would take hold of it with his left hand and say, "Straighten yourselves, align your rows."
حدثنا مسدد حدثنا حميد بن الأسود حدثنا مصعب بن ثابت عن محمد بن مسلم
بهذا الحديث قال إن رسول الله ﷺ كان إذا قام إلى الصلاة أخذه بيمينه ثم التفت فقال اعتدلوا سووا صفوفكم ثم أخذه بيساره فقال اعتدلوا سووا صفوفكم
No references are available.
[Its chain of transmission is daif] Bayhaqi 2/22 narrated it from the hadith of Abu Dawud, through him. See also the previous hadith.