Sahih Muslim 154
صحيح مسلم#154SahihSalim reported on the authority of his father that the Prophet (may peace and blessings be upon him) heard a man censuring his brother regarding modesty. Upon this the Prophet remarked:Modesty is part of Iman (faith)
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: 1:61