(3) باب السُّنَّةِ فِي الأَذَانِ
It was narrated that Bilal said:
"The Messenger of Allah commanded me (with Tathwib) in the Adhan for Fajr, and he forbade me to do so in the Adhan for 'Isha'." (ID)
Reference (ID): Sunan Ibn Majah 715 (ID)
In-book reference (ID): Book 3, Hadith 10 (ID)
English translation (ID): Vol. 1, Book 3, Hadith 715 (ID)