We were traveling with the Messenger of Allah ﷺ while he was fasting. When the sun set, he said, "Bilal, get down and prepare us a drink."Bilal said, "Messenger of Allah, perhaps you should wait until evening."He said, "Get down and prepare us a drink."Bilal said, "Messenger of Allah, there is still daylight upon you."He said, "Get down and prepare us a drink."So Bilal got down and prepared the drink, and the Messenger of Allah ﷺ drank. Then he said, "When you see night approaching from this direction, the fasting person has broken his fast," and he pointed with his finger toward the east.
حدثنا مسدد حدثنا عبد الواحد حدثنا سليمان الشيباني قال سمعت
سرنا مع رسول الله ﷺ وهو صائم فلما غربت الشمس قال يا بلال انزل فاجدح لنا قال يا رسول الله لو أمسيت قال انزل فاجدح لنا قال يا رسول الله إن عليك نهارا قال انزل فاجدح لنا فنزل فجدح فشرب رسول الله ﷺ ثم قال إذا رأيتم الليل قد أقبل من ها هنا فقد أفطر الصائم وأشار بأصبعه قبل المشرق
Sourced from Bukhari, Fasting, chapter on when it becomes permissible for the fasting person to break the fast, hadith no. 1955, and Muslim, Fasting, chapter on the explanation of the time when fasting ends and the day comes to an end, hadith no. 1101, from the hadith of Abu Ishaq Sulayman Shaybani with this same chain.