Silsilat al-Ahadith al-Sahihah

Iyas bin Mu'awiyah bin Qurrah Muzani narrates from his father, who narrates from his grandfather Qurrah bin Muzani (may Allah be pleased with him), who says: We were with the Messenger of Allah (peace and blessings be upon him) when the topic of modesty was mentioned. The companions said: O Messenger of Allah! Is modesty also a part of religion? The Messenger of Allah (peace and blessings be upon him) said: "Indeed, modesty, chastity, humility, and understanding are from faith (humility here means humility of speech, not of heart). The increase that these matters bring in the Hereafter is greater than the decrease that occurs in this world. Indeed, miserliness, immorality, and foul speech are from hypocrisy; these things cause loss in the Hereafter and increase in this world. But the decrease that these matters cause in the Hereafter is greater than the increase that occurs in this world." Iyas said: I narrated this hadith to Umar bin Abdul Aziz, then at his command, I dictated it, then he wrote this hadith in his own handwriting, then when he led us in the Zuhr and Asr prayers, that letter was in his palm, he had not put it away.