Musnad Ahmad 30:1802

Qutaybah ibn Sa'id narrated to us, Bakr ibn Mudar narrated to us, from Yazid ibn al-Had, from Muhammad ibn Ibrahim, from 'Isa ibn Talhah, from Abu Hurairah, that he heard the Messenger of Allah, peace and blessings of Allah be upon him, say: "Indeed, the servant speaks a word for which he slips into the Fire a distance further than what is between the East and the West."