for Muhammad ibn al-Hasan had openly refuted Mālik and the people of Medina, and he was the first person known (1) to have issued a refutation of his opponents (2). Al-Shāfi‘ī therefore examined (3) his arguments and defended those views of the people of Medina that he found to be correct. For the most part, he championed the school of the people of the Hijaz and the hadith scholars.
Then ‘Īsā ibn Abān wrote a book in which he set out to refute al-Shāfi‘ī, so Ibn Surayj wrote a book refuting ‘Īsā ibn Abān.
Likewise, Ahmad ibn Hanbal did not study under al-Shāfi‘ī; rather, he sat with him, just as al-Shāfi‘ī sat with Muhammad ibn al-Hasan, and each benefited from the other.
Al-Shāfi‘ī and Ahmad agreed on their foundational principles to a greater extent than al-Shāfi‘ī and Muhammad ibn al-Hasan did. Al-Shāfi‘ī was more than ten years older than Ahmad.
Al-Shāfi‘ī first came to Baghdad sometime in the 180s AH, during the lifetime of Muhammad ibn al-Hasan and after Abū Yūsuf’s death. He then came there a second time sometime in the 190s AH, and on this visit Ahmad met with him.
Overall, none of these four imams took any of the foundational principles of jurisprudence from Ja‘far. They did, however, transmit hadiths from him just as they transmitted from others, and the hadiths they transmitted from others are many times more numerous than those they transmitted from him. There is simply no comparison between al-Zuhrī’s hadiths and Ja‘far’s, either in strength or number.
Al-Bukhārī also doubted some of his hadiths when he heard from Yahyā ibn Sa‘īd