(3) باب السُّنَّةِ فِي الأَذَانِ
It was narrated from 'Awn bin Abu Juhaifah that his father said:
"I came to the Messenger of Allah in Abtah, when he was in a red tent. Bilal came out and gave the call to prayer, turning around and putting his fingers in his ears."
Reference: Sunan Ibn Majah 711
In-book reference: Book 3, Hadith 6
English translation: Vol. 1, Book 3, Hadith 711