Musnad Ahmad 1034:146

Hammad ibn Khalid narrated to us, from Mahdi, from Wasil al-Ahdab, from Abu Wa’il, who said: It was said to Hudhayfah, "A certain man spreads gossip (namim)." Hudhayfah said: I heard the Prophet, peace and blessings of Allah be upon him, say: "A gossip-monger (nammam) shall not enter Paradise."