From Sahih Muslim (Hadith 292):
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 (ﷺ) saying: The tale-bearer will not enter Paradise
Reference: Muslim 292