شرح أصول السنة للامام أحمد
An Explanation of Imam Ahmad’s Foundations of The Sunnah
The creed (‘aqeedah) of Ahlus-Sunnah wal-Jamaa’ah was penned down by Imaam Ahmad ibn Hanbal (may Allaah’s mercy be upon him) in his great work Usoolus-Sunnah translated as The Foundations of the Sunnah.
Usool us-Sunnah, then though it is small in size it is indeed great in meaning. Abu Ya’la al-Hanbali (died 526H) stated (Tabaqaat al-Hanaabilah 1/241):
If one was to travel to China in search of it – it would be no mean feat.