Sahih Muslim 977
صحيح مسلم#977SahihHammam b. Munabbih reported:This is what was transmitted to us by Abu Huraira from the Messenger of Allah (ﷺ) and, while making a mention of a few ahadith, said: (The Messengerof Allah directed us thus): Establish rows in prayer, for the making of a row (straight) is one of the merits of prayer
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih Muslim is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 4:139