The Messenger of Allah ﷺ said, "Do not be deceived by the call to prayer of Bilal, nor by this whiteness, until the dawn breaks like this and like this," meaning across.Abu Dawud said, "He spread out his hands to the right and to the left, extending them."
أخبرنا محمود بن غيلان قال حدثنا أبو داود قال حدثنا شعبة أنبأنا سوادة بن حنظلة قال سمعت
قال رسول الله ﷺ لا يغرنكم أذان بلال ولا هذا البياض حتى ينفجر الفجر هكذا وهكذا يعني معترضا قال أبو داود وبسط بيديه يمينا وشمالا مادا يديه
Takhrij 1: Reported by Muslim, Fasting, chapter on explaining that entering the fast [begins with the sighting of the crescent] etc., hadith no. 42/1094, from the hadith of Abu Dawud Tayalisi with the same wording. It is also found in Kubra, hadith no. 2481, and Musnad Tayalisi, hadith no. 897.