Imām Abū Dāwūd on Imām Aḥmad bin Ḥanbal

Abū Bakr bin Abū Dāwūd (may Allāh have mercy upon then) said: “I heard my father say that Aḥmad bin Ḥanbal is at the forefront of all who ever carried a pen and an inkpot. i.e., in his time”