The Messenger of Allah ﷺ passed by a man who was admonishing his brother about being too modest. The Messenger of Allah ﷺ said, "Leave him, for modesty is part of faith."
أن رسول الله ﷺ مر على رجل وهو يعظ أخاه في الحياء، فقال رسول الله ﷺ: دعه فإن الحياء من الإيمان.
Malik narrated it in Husn al-Khuluq (10), from Ibn Shihab, from Salim, from Abdullah bin Umar, and he mentioned the hadith. Bukhari narrated it in al-Iman (24), from Abdullah bin Yusuf, from Malik, with the same chain. Muslim narrated it in al-Iman (36) through several routes from Zuhri.