The Messenger of Allah ﷺ used to straighten our rows so meticulously that it was as if he were straightening arrow shafts with them, until he saw that we had grasped what he wanted from us.Then one day he came out and stood ready to begin the prayer, almost saying the takbir, when he noticed a man whose chest was protruding from the row. He said, "Servants of Allah, you must straighten your rows, or Allah will set your faces in opposition to one another."
حدثنا يحيى بن يحيى أخبرنا أبو خيثمة عن سماك بن حرب قال سمعت
ا كان رسول الله ﷺ يسوي صفوفنا حتى كأنما يسوي بها القداح حتى رأى أنا قد عقلنا عنه ثم خرج يوما فقام حتى كاد يكبر فرأى رجلا باديا صدره من الصف فقال عباد الله لتسون صفوفكم أو ليخالفن الله بين وجوهكم