Musnad Abu Ya'la al-Mawsili 118:38

Muhammad ibn Abd al-Rahman ibn Sahm al-Antaki narrated to us, Isa ibn Yunus narrated to us, from Mu'awiyah ibn Yahya al-Sadafi, from al-Zuhri, from Anas ibn Malik, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "Indeed, for every religion there is a character, and the character of this religion is modesty."