In his amazing and monumental explanation of Imaam al-Aajurree's "al-Sharee'ah", Shaykh Rabee bin Haadee al-Madkhali, writes, when disscussing the issues of Allaah's qadar and kalaam (1/385):

And the Mu'tazilah - may Allaah disfigure them - use His saying as proof: (اللَّهُ خَالِقُ كُلِّ شَيْءٍ) "Allaah is the creator of every thing" (39:62), they said: And the Qur'an is a "thing", hence it is from the created things. This is from strange aspects of their misguidance. This verse itself is a refutation of them (اللَّهُ خَالِقُ كُلِّ شَيْءٍ) "Allaah is the creator of every thing" (39:62), they use to prove that the Qur'an is created, then they expel the created actions of the servants from this (verse), look at the misguidance. Meaning, they hold that this verse applies to the Qur'an such that it (the Qur'an) enters into the generality of "every thing" and at the same time they forget that the actions of the servants enter into it (every thing) first and foremost. But they remove (the actions) from this generality and say: The actions of the servants are not created by Allaah. So the proof is the very same verse. They say the actions of the servants are not created by Allaah, that He does not wish them (to come to be) and the servant creates his own action, yet Allaah says, (وَاللَّهُ خَلَقَكُمْ وَمَا تَعْمَلُونَ) "And Allaah created you and whatever you do (make)" (37:96). And many verses have stated that nothing takes place in the creation except by His permission, will and wish and from them are the actions of the servants (وَمَا تَشَاؤُونَ إِلَّا أَن يَشَاء اللَّهُ), "And you do not will except as Allaah wills" (76:30).

Notes

01. The Mu'tazilah are a kalam group who founded speech about Allaah, His Names, Attributes and Actions upon the conceptual baggage and terminology of Aristotle. This was taken from them by the Ash'aris and Maturidis who share in the usool (foundations) of the Mu'tazilah in this field, but differ with them in subsidiary matters. The Mu'tazilah claimed the Qur'an is created because speech (kalaam) cannot be established with Allaah as an attribute or as something tied to another attribute, iraadah (wish) as the presence of attributes and wilful actions necessitates Allaah is a body (jism) and this would invalidate the proof for establishing the universe (a collection of bodies) is originated. This is what Ahl al-Kalaam founded their theology upon. This meant that the Qur'an had to be accounted for and so the Mu'tazilah said the Qur'an is a created entity, and is said to be Allaah's speech in the same way that a mosque is said to be Allaah's house or a messenger is said to be Allaah's messenger. In order to prop up this same futile theology operating upon corrupt theoretical foundations, the Ash'arites followed the school of Ibn Kullaab who invented the kalaam nafsee concept and the two Qur'an doctrine it necessitated: An eternal uncreated single indivisible meaning in the self of Allaah and a created Arabic Qur'an that is recited, heard and memorized with the servants. Both of these doctrines necessitate that the Qur'an is created, a statement of kufr, except that the Mut'azilah are apparent and open and the Ash'arites are conniving, deceptive and hypocritical with some exceptions, some of them show moments of (discreet) honesty (in some of what they write): See here and here (al-Bayjuri), here (al-Razi), here (al-Juwaynee) and here ( al-Buti).

02. In the topic of al-Qadar, the Mu'tazilah took the doctrine of the Qadariyyah whereas the Ash'aris took the doctrine of the Jabariyyah (from al-Jahm bin Safwan), and thus the Mu'tazilah held that man's actions are outside the domain of Allaah's will and creative power. Hence, man created his own actions in reality. When these innovated groups (Mu'tazilah, Ash'aris) founded their religion upon other than submission to the revealed texts and employed their reason, making it superior to revelation, it was inevitable that contradictions appear across different disciplines and subject areas in which they give their opinions. Examples of these are many amongst the Ash'aris, but here amongst the Mu'tazilah there is a clear contradiction in that in the field of the Sifaat, they claim that the Qur'an is created because of the verse (اللَّهُ خَالِقُ كُلِّ شَيْءٍ) "Allaah is the creator of every thing" (39:62), the Qur'an being a "thing" and then in the field of Qadar, they said Allaah is not the creator of man's actions and expel them from coming within "every thing". An example of the Ash'arite's contradictions is that they say in the field of Qadar that Allaah does not have objectives or wisdoms in his actions (because this invalidates Tawhid). Then in arguing for and validating Prophethood they rely upon the proof through miracles in which they argue that if a false prophet made claim to prophethood Allaah would falsify and invalidate his claim and his alleged miracle, so here Allaah would be acting with a wisdom and objective (without it invalidating Tawhid). This contradicts what they assert in the field of Qadar. This is the nature of falsehood, it is not coherent, but varies, changes, self-conflicts and self-destructs. This is what the Shaykh has pointed out here with respect to the Mu'tazilah, whereby their falsehood forces them throw one part of the Book against another.