“The
Messenger
of Allah (ﷺ) used to straighten the rows until he made
them like a
spear or an arrow-shaft. Once he saw a man’s chest
(sticking out)
so the Messenger of Allah (ﷺ) said: ‘Make your rows
straight or
Allah will create division among you.’”
Sunan Ibn Majah Book 5, Hadith 192