The adhan (call to prayer) of Bilal should not prevent you from taking a meal shortly before dawn, not does the whiteness of horizon (before dawn) in this way (vertically) until it spreads out horizontally.
Hadith Commentary: The False Dawn & Pre-Dawn Meal
This narration from Sunan Abi Dawud 2346 in the Book of Fasting (Kitab Al-Siyam) addresses the distinction between the false dawn (Fajr al-Kadhib) and the true dawn (Fajr al-Sadiq), which determines when the fasting day begins.
The Two Dawns Explained
The vertical whiteness refers to the false dawn - a temporary, upright column of light that appears in the sky but does not signify the beginning of Fajr time. The horizontal spreading refers to the true dawn - when light spreads across the horizon, marking the actual start of the fasting day.
Bilal's early adhan was given during the time of false dawn to awaken people for Tahajjud prayer and to prepare suhur, not to indicate the commencement of fasting.
Juridical Significance
This hadith establishes that Muslims may continue eating and drinking until the true dawn appears, even after hearing an early adhan. The ruling protects against premature cessation of suhur and ensures proper observance of the fast's timing as prescribed in Islamic law.
Scholars emphasize that one should rely on visual confirmation of true dawn or established timetables based on astronomical calculations rather than solely on adhan times.