Fiqh-us-Sunnah Volume 2, Supererogatory Prayer, Fiqh 2.064A.

Section : Straightening the rows and filling the gaps.

It is preferred for the imam to order the followers to straighten the rows and fill in any gaps before he starts the salah.

Anas relates: “The Prophet would turn his face to us before he began the salah and he would say: ‘Be close together and straighten your rows.'” This is related by al-Bukhari and Muslim. He also reported that the Prophet would say: “Make your rows straight for the straightening of the rows is part of the completion of the salah.”

An-Nu’man ibn Bashir says: “The Prophet would straighten us in our rows as one straightens an arrow, until he saw that we had learned from him. One day, he saw a person with his chest sticking out and he said: ‘You had better straighten your rows or Allah will cause differences among you.”‘ This is related by the five. At-Tirmizhi says it is sahih.

Abu Umamah reports that the Prophet sallallahu alehi wasallam said: “Straighten your rows and put your shoulders close to each other and be gentle with each other and fill in the gaps for the Satan passes through what is between you like small sheep [are able to pass through gaps].” This is related by Ahmad and at-Tabarani with a chain that has no fault in it.

Anas reports that the Messenger of Allah said: “Complete the front row, then the ones after it, and if there is any incompletion, it should be in the last row.” This is related by Abu Dawud, an-Nasa’i, and al-Baihaqi.

Ibn ‘Umar says: “There is no step that carries a greater reward than the step a man takes to an empty gap in a row in order to fill it.” This is related by al-Bazar with a hasan chain.

Ibn ‘Umar also related that the Messenger of Allah said: “Whoever connects a row, Allah will join him. Whoever cuts off a row, Allah will cut him off.” This is related by An-Nasa’i, al-Hakim, and Ibn Khuzaimah.

Jabir ibn Samrah says: “The Prophet sallallahu alehi wasallam came to us and said: ‘Why don’t you make the rows like the angels make their rows in the presence of their Lord?’ We asked: ‘O Messenger of Allah, how do the angels make their rows in the presence of their Lord?’ He replied: ‘They complete the first row and stand closely together, side by side, in the row.'” This is related by the group, save al-Bukhari and at-Tirmizhi.