Please explain to me the following Hadeeth: Narrated An-Nu'man bin Bashir (R.A), the Prophet, sallallaahu 'alayhi wa sallam, said, "Straighten your rows or Allah will alter your faces". [Al-Bukhaari]

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

An-Nu'maan Ibn Basheer narrated: “I heard the Prophet saying: “You have to straighten your rows (in prayer) or else Allah (my He be Exalted) will overturn your faces.” [Al-Bukhari and Muslim]

Another narration by Ibn Maajah which was ruled as authentic by al-Albani, reads: “Straighten your rows lest Allah overturn (reverse) your faces.”

What is meant by straightening the rows is to line up properly on a straight line, or filling the gaps that may be found in that row. As for the meaning of “overturning” the faces, it is a matter of disagreement among the scholars: does it mean literally disfiguring the face by turning it to the backside? Or does it have a metaphorical connotation?

Some scholars hold the opinion that it is to be taken metaphorically to mean causing discord and enmity, as when one says: “the face of so and so (person) has turned on me”, meaning he has shown me a frowning or displeased face. The preponderant opinion according to Imam An-Nawawi is to take it metaphorically. He cited as evidence the narration of Abu Daawood and Ahmad, which reads: “Straighten your rows; (I swear) by Allah that you have to straighten your rows or else Allah will make your hearts different.”

Another point which supports An-Nawawi 's opinion is the Hadeeth narrated by Al-Baraa' Ibn 'Azib who narrated that the Prophet said: “Straighten your rows lest your hearts differ.” [Ad-Daarimi and classified as authentic by Shaykh Hussayn Assad in ‘Sunan Ad-Daarim'i and by Al-Albaani in Saheeh al-Jaami’]

Allah knows best.