Straighten your rows, for indeed, straightening the rows is part of the perfection of the prayer. [Sahih/Authentic] - [Al-Bukhari and Muslim]
"«سَوُّوا صُفُوفَكُم، فإِنَّ تَسوِيَة الصُّفُوف من تَمَام الصَّلاَة». [صحيح.] - [متفق عليه.]"