Straighten your rows

 عَنْ أَنَسٍ، عَنِ النَّبِيِّ صلّى الله عليه وسلّم قَالَ: سَوُّوا صُفُوفَكُمْ فَإِنَّ تَسْوِيَةَ الصُّفُوفِ مِنْ إِقَامَةِ الصَّلاَةِ

Hazrat Anas^ra narrated that the Prophet^sa said: “Straighten your rows, for indeed, aligning the rows is part of establishing the prayer.”

(Sahih al-Bukhari, Kitab al-adhan, Bab iqamati s-saffi min tamami s-salah, Hadith 723)