Weak
graded by Al-Albani
Mishkat al-Masabih 1098
Narrator:Anas ibn Mālik
وَعَنْ أَنَسٍ قَالَ: كَانَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَقُولُ عَنْ يَمِينِهِ: «اعْتَدِلُوا سَوُّوا صُفُوفَكُمْ» . وَعَنْ يَسَارِهِ: «اعْتَدِلُوا سَوُّوا صُفُوفَكُمْ» . رَوَاهُ أَبُو دَاوُ
Anas told how God’s Messenger used to say to those on his right, ‘‘Keep straight and straighten your rows," and say the same to those on his left. Abu Dawud transmitted it.
Cited in Mishkat al-Masabih (No. 1098).