And when al-Ma’mūn reached the frontier at Tarsus, he wrote to his deputy in Iraq, Ishāq ibn Ibrāhīm, ordering that people be put to the test. Ishāq summoned the scholars, jurists, and judges, but they refused to assent or comply. He reported their response to al-Ma’mūn, who wrote a second letter, saying of the two judges, Bishr ibn al-Walīd and ʿAbd al-Rahmān ibn Ishāq: “If they do not comply, behead them.” Regarding the others, he said: “If they do not comply, put them in chains and send them to me.”

The two judges complied, telling their companions that they were acting under coercion. Most of the others complied before being chained, upon seeing the threatened punishment. Six men refused, so he had them chained. Once they were chained, the remaining men complied except for two: Ahmad ibn Hanbal and Muhammad ibn Nūh al-Naysābūrī. These two were sent to al-Ma’mūn in chains. Muhammad ibn Nūh died on the journey, and al-Ma’mūn died before Ahmad reached him. His brother Abū Ishāq succeeded him, and Ahmad ibn Abī Du’ād assumed the judgeship. Ahmad ibn Hanbal remained imprisoned from the year eighteen until the year twenty.

They then summoned him and debated with him for several days. He refuted their arguments, demonstrated their unsoundness, and showed that they had produced no evidence for their claims from the Quran, the Sunnah, or transmitted reports. He also explained that they had no right to introduce an innovated doctrine, compel people to agree with them, and punish those who opposed them. People may only be bound by what Allah and His Messenger have made binding upon them, and only those who disobey Allah and His Messenger may be punished. For making things obligatory or forbidden, assigning reward and punishment, and declaring someone an unbeliever or a sinner belong to Allah and His Messenger; no one else has authority to rule on these matters. People are only to deem obligatory what Allah and His Messenger have made obligatory, and to deem forbidden