hadith

 Sahih Bukhari  صحیح بخاری

Hadith # 2656

Translation:

Narrated Abdullah bin Umar (RA): 

The Prophet ﷺ said, " Bilal (RA) pronounces the Adhan when it is still night (before dawn), so eat and drink till the next Adhan is pronounced (or till you hear Ibn Um Maktums Adhan)." Ibn Um Maktum was a blind man who would not pronounce the Adhan till he was told that it was dawn.