(12) باب بَيَانِ عَدَدِ شُعَبِ الْإِيمَانِ وَأَفْضَلِهَا وَأَدْنَاهَا وَفَضِيلَةِ الْحَيَاءِ وَكَوْنِهِ مِنْ الْإِيمَانِ
Salim 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).
Reference: Sahih Muslim 36 a
In-book reference: Book 1, Hadith 61
USC-MSA web (English) reference(deprecated numbering scheme): Book 1, Hadith 57