[Machine] The Messenger of Allah ﷺ said, "Do not be deceived by your sahoor (pre-dawn meal) by the Adhan of Bilal or the whiteness of the morning. Like this." Then he raised his hands until they reached the sky and extended his hand."
قَالَ رَسُولُ اللهِ ﷺ «لَا يَغُرَّنَّكُمْ مِنْ سُحُورِكُمْ أَذَانُ بِلَالٍ وَلَا بَيَاضُ الصُّبْحِ هَكَذَا وَرَفَعَ يَدَيْهِ حَتَّى يَطِيرَ فِي الْأُفُقِ وَعَرَّضَ بِيَدِهِ»
The Adhan of Bilal may not mislead you with regard to your food at the commencement of the fast, nor the vertical (streaks) of whiteness in the horizon (for it is an indication of false dawn). You should stop eating (food) till (the whiteness) spreads like it. Hammad narrated it and with the gesture of his band he explained, the horizontal position (of the streaks of light).
قَالَ رَسُولُ اللَّهِ ﷺ لاَ يَغُرَّنَّكُمْ مِنْ سَحُورِكُمْ أَذَانُ بِلاَلٍ وَلاَ بَيَاضُ الأُفُقِ الْمُسْتَطِيلُ هَكَذَا حَتَّى يَسْتَطِيرَ هَكَذَا وَحَكَاهُ حَمَّادٌ بِيَدَيْهِ قَالَ يَعْنِي مُعْتَرِضًا
The Adhan of Bilal should not mislead you nor the whiteness (of the pillar) of dawn, for it is not the whiteness of the true dawn, but that of the false dawn which is vertical like a pillar and you can eat food till the streaks of whiteness spread like it. (Using translation from Muslim 1094b)
قَالَ رَسُولُ اللهِ ﷺ لَا يَغُرَّنَّكُمْ أَذَانُ بِلَالٍ وَلَا هَذَا الْبَيَاضُ لِعَمُودِ الصُّبْحِ حَتَّى يَسْتَطِيرَ