Musannaf Ibn Abi Shayba 3:3900

Ali ibn Mushir narrated to us, from al-Shaybani, from Abd al-Rahman ibn al-Aswad, from his father, who said: I was sitting with Abdullah in his house, and the sun set. Abdullah said: "Establish the prayer at the decline of the sun until the darkness of the night." Then he said: "This, by Allah, besides whom there is no god, is when the fasting person breaks his fast, and the time for this prayer has arrived."