Know that what we mention about the issue of the Qadar is not delving into the issue in the inappropriate way that the Prophet forbade when he said,
إذَا ذُكِرَ القَدَرُ فأَمْسِكُوا
[which means] “If Destiny is mentioned, then hold back,” as narrated by At–Tabaraniyy, because this is the explanation of the Qadar with which the religious text came. As for what is prohibited, that is delving to reach its secret.
Ash-Shafi^iyy and Ibn ^Asakir narrated from the route of ^Aliyy that he said to the one who was asking about the Qadar, “It is the secret of Allah, do not delve into it,” but the man insisted. ^Aliyy said to him, “Then if you refused to stop, know that certainly it is a matter between two matters; it is not compulsion and it is not unrestricted free will.”
Also know that the Messenger of Allah dispraised the deniers of the Qadar, and they are of factions. Among them are those who said that the slave is in charge of all of his voluntary deeds, and among them are those who said that he is the creator of evil, not the good, and both factions are blasphemers. The Messenger of Allah said,
القَدَرِيَّةُ مَجُوسُ هَذِهِ الأُمَّةِ
[which means] “The Qadariyyah are the Majus of this nation,” and in one narration of this hadith,
لِكُلّ أمَّةٍ مَجُسٌ، ومَجُوسُ هذِهِ الأُمَّةِ الذينَ يَقُولونَ لا قَدَرَ
[which means] “Every nation had its Majus, and the Majus of this nation are those who say ‘There is no destiny.’” Narrated by Abu Dawud from the route of Hudhayfah from the Prophet.
In the book of Al-Qadar by Al-Bayhaqiyy, and in the book Tahdhibul-Athar by Imam Ibn Jarir At–Tabariyy, may Allah have Mercy upon both of them, [it is narrated] from the route of ^Abdullah Ibn ^Umar that the Messenger of Allah said,
صِنْفَان من أُمَّتي ليسَ لَهُما نَصِيبٌ في الإسْلامِ القَدَرِيَّةُ والمرجئَةُ
[which means] “Two factions from my nation have no share in Islam: the Qadariyyah [those who deny the Qadar] and the Murji’ah [those who deny that believers will be punished].” The Mu^tazilah are the Qadariyyah because they made Allah and the slave equal by negating the Power of Allah over what the slave has power over. As if they are confirming [many] creators in reality, just like the Majus have confirmed two creators, a creator for good, who according to them is the light, and a creator for evil, who according to them is the darkness.