صحيح مسلم

'Abdullah b. Abi Aufa reported: We were with the Messenger of Allah (ﷺ) on a journey during the month of Ramadan. When the sun had sunk he said: So and so, get down (from your ride) and prepare the meal of parched barley for us. He said: Messenger of Allah, still (there is light of) day. He (the Holy Prophet) said: Get down and prepare meal of parched barley for us. So he got down and prepared the meal of parched barley and offered him, and the apostle of Allah (ﷺ) drank that (liquid meal). He then told with the gesture of his hand that when the sun sank from that side and the night appeared from that side, then the observer of the fast should break it.