Sahih al-Bukhari Book 68, Hadith 46
We were with Allah's Messenger (ﷺ) on a journey, and when the sun set, he said to a man, "Get down and
prepare a drink of Sawiq for me." The man said, "O Allah's Messenger (ﷺ)! Will you wait till it is evening?"
Allah's Messenger (ﷺ) again said, "Get down and prepare a drink of Sawiq." The man said, "O Allah's
Apostle! Will you wait till it is evening, for it is still daytime. " The Prophet (ﷺ) again said, "Get down
and prepare a drink of Sawiq." So the third time the man got down and prepared a drink of sawiq for
him. Allah's Messenger (ﷺ) drank thereof and pointed with his hand towards the East, saying, "When you see
the night falling from this side, then a fasting person should break his fast."
I heard the Prophet (ﷺ) saying, "Afflictions will emerge from here," pointing towards the East.
The Prophet (ﷺ) said, "The call (or the Adhan) of Bilal should not stop you from taking the Suhur-meals for Bilal calls (or pronounces the Adhan) so that the one who is offering the night prayer should take a rest, and he does not indicate the daybreak or dawn." The narrator, Yazid, described (how dawn breaks) by stretching out his hands and then separating them wide apart.