(17) باب قَوْلِ النَّبِيِّ صلى الله عليه وسلم " لاَ يَمْنَعَنَّكُمْ مِنْ سَحُورِكُمْ أَذَانُ بِلاَلٍ "
Narrated `Aisha:
Bilal used to pronounce the Adhan at night, so Allah's Messenger (ﷺ)? said, "Carry on taking your meals (eat and drink) till Ibn Um Maktum pronounces the Adhan, for he does not pronounce it till it is dawn.
Reference: Sahih al-Bukhari 1918, 1919
In-book reference: Book 30, Hadith 28
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 3, Book 31, Hadith 142