The Book of Faith (Kitab Al-Iman)
Muslim :: Book 1 : Hadith 191
It is narrated on the authority of Hammam b. al-Harith: We were sitting with Hudhaifa in the mosque. A man came and sat along with us. It was said to Hudhaifa that he was the man who carried tales to the ruler. Hudhaifa remarked with the intention of conveying to him: I have heard the Messenger of Allah (may peace be upon him) saying: The tale-bearer will not enter Paradise.