Nafi reported,

Umar bin Khattab used to give orders that the rows be straightened, and when the men came to him and reported that the rows were straight, he would pronounce the takbir.

Malik 384

Sahih

حدثني يحيى عن مالك

عن نافع

أن عمر بن الخطاب كان يأمر بتسوية الصفوف فإذا جاءوه فأخبروه أن قد استوت كبر

مالك 384صحيح
Contents
Reference
Commentary
Ayat
Collection
Muwatta Malik
Book
Shortening prayer while traveling
Numbering
Laithi 384
Malik 384