Abu Dawood: Hadith 2353

We went along with the Messenger of Allah (ﷺ) while he was fasting. When the sun set, he said to Bilal: Bilal, come down and prepare barley beverage for us. He said: Messenger of Allah, would that you waited for the evening. He said: Come down and prepare barley beverage for us. He said: Messenger of Allah, the say still remains on you (i.e. there remains the brightness of the day). He said: Come down and prepare barley drink for us. So he came down and prepared barley drink. The Messenger of Allah (ﷺ) drank it and said: When you see that the night approaches from this side, he who fasts has reached the time to break it ; and he pointed to the east with his finger.