Musnad Ahmad 1034:214

Yahya ibn Adam narrated to us, Habib ibn Salim al-Absi narrated to us, from Bilal al-Absi, from Hudhayfah, that when someone died for him, he would say: "Do not inform anyone about him, for I fear that it may be a *na'i* (announcement of death). Indeed, I heard the Messenger of Allah, peace and blessings of Allah be upon him, forbidding *na'i*."