Sahih Muslim Book 1, Hadith Number 59.

Chapter : Concerning the branches of Iman.

It is narrated on the authority of ‘Imran b. Husain that the Prophet (may peace and blessings be upon him) said: Modesty brings forth nothing but goodness. Bushair b. Ka’b said: It is recorded in the books of wisdom, there lies sobriety in it and calmness of mind in it, Imran said: I am narrating to you the tradition of the Messenger of Allah (may peace and blessings be upon him) and you talk of your books.