Musnad Abu Ya'la al-Mawsili 250:9

Abu Yasir ‘Ammar narrated to us, Abu al-Miqdam Hisham ibn Ziyad narrated to us, he said: My father narrated to me, from Yusuf ibn ‘Abd Allah ibn Salam, from his father, that the Prophet (peace and blessings of Allah be upon him) said: "Modesty is from faith."