(17) باب وَقْتِ السُّحُورِ
Addressing (the people) Samurah b. Jundub reported the Messenger of Allah (ﷺ) as saying:
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.
Reference: Sunan Abi Dawud 2346
In-book reference: Book 14, Hadith 34
English translation: Book 13, Hadith 2339