Musnad Ahmad 2:301

Waki’ narrated to us, Hisham bin ‘Urwah narrated to us, from his father, from ‘Asim bin ‘Umar, from his father, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "When the night comes from here, and the day departs from here, then the fasting person has broken his fast."