Al-Husain Ibn Yazīd Al-Karabīsī (died 248H): He was to first of those to say:
“My recital of the Qur’ān is created.” And this was the innovation of al-Lafdh. So Imām Ahmad Ibn Hanbal (رحمه الله) declared him to be an innovator, and boycotted him so that these new beliefs that were unheard of in the time of the Salaf would not lead to the saying that the Qur’ān is created. Ibn ‘Adiyy said: “I heard Muhammad Ibn Abdillāh as-Sīrafī ash-Shāfi’ī say to his students: Take a lesson from the affair of Husain al-Karabīsī and Abu Thawr. So Abu Thawr did not reach even a tenth of the knowledge and memorisation of al-Karabīsī! Then Imām Ahmad Ibn Hanbal spoke against al-Karabīsī in the affair of al-lafdh, so he fell. And he praised and extolled Abu Thawr, so he was elevated in rank due to his holding fasting to the Sunnah.” (See As-Siyar, 12/79, of Adh-Dhahabī رحمه الله)
Imām Ahmad did not excuse Karabīsī due to his immense knowledge, rather he refuted him on the basis of his innovation
Reflect over the speech of as-Sīrafī and understand that the affair revolves around holding fast to the path of Salafiyyah, and in speaking the truth, acting upon it and remaining steadfast. It was due to this that the imāms of Sunnah would praise a person and elevate his rank. As for the treacherous one who plays and fools around with the principles and the usūl of Salafiyyah, calling to innovation, then he is rightfully refuted and abandoned until he repents, and returns to the truth. And if he continues stubbornly then he written with the people of Hadīth as a liar, a person of misguidance – and his affair remains like that till his death and beyond, as was the case with Al-Karabīsī. Sitting on the fence is not an option when the truth has been made distinct from falsehood for that, in reality, is a betrayal of the truth.