Is it permissible to declare al-Ma'mun and those who followed him disbelievers for compelling people to say that the Qur'an is created?

Question:
May Allah reward you, Honorable Shaykh. This questioner asks: Is it permissible to declare al-Ma'mun and those who followed him in compelling Muslims to say that the Qur'an is created disbelievers? Is it permissible to declare al-Ma'mun and those who followed him in compelling Muslims to say that the Qur'an is created disbelievers?

Answer:
Al-Ma'mun was one who practiced ta'wil (figurative interpretation) and followed the Mu'tazilah, so it is not permissible to declare him a disbeliever. As for Bishr al-Murisi and Ibn Abi Du'ad, there is no doubt that it is permissible to declare them disbelievers because they knew this, taught it, and called people to it. The one who calls to bid'ah (religious innovation) is declared a disbeliever if he calls to it, knowing that it is an innovation and contrary to the Shari'ah; he is declared a disbeliever for that.
As for al-Ma'mun, he is among those who are excused by following a scholar without knowing his evidence (taqlid) and figurative interpretation (ta'wil). Yes. Therefore, Imam Ahmad did not declare al-Ma'mun a disbeliever. Yes. In fact, he did not even curse him or rebel against his rule. He did not rebel against al-Ma'mun or incite people against al-Ma'mun. He was always patient with the trial and test. And when they said to him, he said, "Bring me evidence." He challenged them, saying, "Bring me evidence from the Qur'an or from the Sunnah." Yes.