Straighten your safs for unity sake

A hadith narrated by Nu’maan bin Basheer (radhiallahu anhu). He says: "Once Rasulullah (sallallahu alaihi wasallam) faced us and said: "Straighten your rows". He repeated this thrice. He then said: "By Allah, you must most certainly straighten your rows or else Allah Ta’ala will disunite your hearts".