(2) باب الأَمْرِ بِشَفْعِ الأَذَانِ وَإِيتَارِ الإِقَامَةِ
Anas reported:
Bilal was commanded (by the Holy Prophet) to repeat the phrases twice in Adhan, and once in lqama. (ES)
Reference (ES): Sahih Muslim 378 d (ES)
In-book reference (ES): Book 4, Hadith 5 (ES)
USC-MSA web (English) reference(deprecated numbering scheme): Book 4, Hadith 739 (ES)