Musnad Ahmad 8:158

Surayj ibn al-Nu'man narrated to us, 'Abd al-'Aziz—meaning al-Darawardi—narrated to us, from Zayd ibn Aslam, from Sa'd ibn Abi Waqqas, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "The Hour will not be established until a people emerge who eat with their tongues just as cattle eat with their tongues."