In Sahih Muslim (2653), it is narrated that ‘Abd-Allah ibn ‘Amr ibn al-‘As (may Allah be pleased with him) said: I heard the Messenger of Allah (peace and blessings of Allah be upon him) say: “Allah wrote down the decrees of creation fifty thousand years before He created the heavens and the earth.”
And the Prophet (peace and blessings of Allah be upon him) said: “The first thing that Allah created was the Pen, and He said to it, ‘Write!’ It said, ‘O Lord, what should I write?’ He said: ‘Write down the decrees of all things until the Hour begins.” Narrated by Abu Dawud, 4700; classed as sahih by al-Albani in Sahih Abi Dawud.
The belief that whatever happens only happens by the will of Allah – whether that has to do with His actions or the actions of created beings.
Allah says concerning His actions (interpretation of the meaning):
“And your Lord creates whatsoever He wills and chooses.” [al-Qasas 28:68]
“and Allah does what He wills.” [Ibrahim 14:27]
“He it is Who shapes you in the wombs as He wills.” [Aal ‘Imran 3:6]
And He says concerning the actions of created beings (interpretation of the meaning):
“Had Allah willed, indeed He would have given them power over you, and they would have fought you.” [al-Nisa 4:90]
“If your Lord had so willed, they would not have done it.” [al-An’am 6:112]
All events, actions and happenings occur only by the will of Allah. Whatever Allah wills happens, and whatever He does not will does not happen.
The belief that all things that happen are created by Allah in their essence, their attributes and their movements.
Allah says (interpretation of the meaning):
“Allah is the Creator of all things, and He is the Wakil (Trustee, Disposer of affairs, Guardian) over all things.” [al-Zumar 39:62]
“He has created everything, and has measured it exactly according to its due measurements” [al-Furqan 25:2]