“The Messenger of Allah (ﷺ) said: ‘Make your rows straight, for straightening the rows is part of completing the prayer.’”
Sunan Ibn Majah Book 5, Hadith 191
← Previous Hadith “The Messenger of Allah (ﷺ) said: ‘Will you not form your rows as the angels form their rows before their Lord?’ We said: ‘How do the angels form their rows before their Lord?’ He said: ‘They complete the first row and they stand close of one another in the line (leaving no gaps between one another).’”

Sunan Ibn Majah Book 5, Hadith 190 Next Hadith → “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