We believe in the divine predestination and decree. Allah Almighty had known all that would happen and written, willed, created, and accurately determined it.
We know with certainty that belief in the divine predestination and decree is the sixth among the pillars of faith. Allah Almighty says: {Indeed, We have created everything according to a determined measure.} [Surat al-Qamar: 49] He, Glorified be He, also says: {And Allah’s command is a decree firmly determined.} [Surat al-Ahzāb: 38] And He, Exalted be He, says: {He has created everything and measured it precisely.} [Surat al-Furqān: 2] In another verse, Allah Almighty says: {The Messenger believes in what has been sent down to him from his Lord, as do the believers. All of them believe in Allah, His angels, and His Books.} [Surat al-Baqarah: 285] Belief in the predestination is part of belief in Allah Almighty, because the predestination is part of His knowledge, determination, and management.
Allah Almighty also says: {It is He Who gives life and causes death. When He decrees a matter, He only says to it, 'Be,' and it is.} [Surat Ghāfir: 68] He Almighty also says: {He alone has the keys of the unseen; no one knows them except Him. He knows what is in the land and sea. Not a leaf falls without His knowledge, nor a grain in the darkness of the earth, nor anything moist or dry, but is [written] in a Clear Record.} [Surat al-An‘ām: 59]
In a Hadīth reported by Abu Hurayrah (may Allah be pleased with him), Jibrīl (peace be upon him) said: "Tell me about faith." He (may Allah's peace and blessings be upon him) said: "To believe in Allah, His angels, His books, His messengers, the Last Day, and to believe in destiny, the pleasant and unpleasant aspects thereof." He said: "You have spoken the truth." [Narrated by Muslim (8), Abu Dāwūd (4695), At-Tirmidhi (2610), An-Nasā’i (4990), and Ibn Mājah (63)]
Muslims unanimously agree that belief in the predestination is one of the pillars of faith. Al-Hāfizh Abu al-Qāsim al-Lālakā’i said: "If there were prevailing and widespread consensus in the world over anything, it would be on this issue (i.e. the predestination). Whoever contradicts it is a stubborn opponent, who is subject to the warning and falls under the verse that says: {But whoever opposes the Messenger after guidance has become clear to him, and follows other than the way of the believers, We will leave him to what he has chosen, and burn him in Hell. What a terrible destination!} [Surat an-Nisā’: 115]" [Sharh Usūl I‘tiqād Ahl As-Sunnah Wa Al-Jamā‘ah (4/726)]
‘Amr ibn Shu‘ayb related from his father that his grandfather reported: A group of people were sitting at the Prophet's door. Some of them said: "Does Allah not say such and such?" Some others said: "Does Allah not say such and such?" The Prophet (may Allah's peace and blessings be upon him) heard that and he came out as if pomegranate seeds had burst into his face (because of anger). He said: "Have you been commanded to do this? - Or have you been created for this purpose? - You are using one part of the Qur’an against another part, and this is what led to the doom of the nations who came before you. You have nothing to do with what is here. See what you have been commanded therein and do it, and what you have been forbidden, refrain from it." [Narrated by Ibn Mājah (85), Ahmad (6845), and this is his version, Al-Hārith ibn Abi Usāmah in Al-Musnad and in Bughyat Al-Bāhith (735), and Ibn Abi ‘Āsim in As-Sunnah (406)]
‘Abdul-Malik - i.e. Ibn Jurayj - related that ‘Atā’ ibn Abi Rabāh reported: I went to Ibn ‘Abbās while he was drawing water from the well of Zamzam and the ends of his clothes became wet, and I said to him: "Some people speak about the predestination (denying it)." He said: "Have they really done it?" I replied in the affirmative. He said: "By Allah, this verse was revealed in connection to none but them: {Taste the agony of Hell! Indeed, We have created everything according to a determined measure} [Surat al-Qamar: 48-49]. Do not visit the sick among them nor offer the funeral prayer for their dead ones. If you showed me one of them, I would definitely gouge out his eye." [Sharh Usūl I‘tiqād Ahl As-Sunnah Wa Al-Jamā‘ah (3/597)]
‘Ubādah ibn as-Sāmit (may Allah be pleased with him) said to his son: "O son, you will not find the taste of the reality of faith until you know that whatever befalls you would not have missed you, and whatever misses you would not have befallen you. I heard the Messenger of Allah (may Allah's peace and blessings be upon him) say: 'The first thing Allah created was the Pen, and He said to it: 'Write.' It said: 'Lord, what should I write?' He said: 'Write the destinies of everything till the coming of the Hour.'' O son, I heard the Messenger of Allah (may Allah's peace and blessings be upon him) say: 'Whoever dies upon something other than this does not belong to me.'" [Narrated by Abu Dāwūd in Sunan (4700) and Ibn Abi ‘Āsim in As-Sunnah (1/51)]
Yahya ibn Ya‘mur reported: The first man who discussed the predestination in Basra was Ma‘bad al-Juhani. I along with Humayd ibn ‘Abdur-Rahmān al-Himyari set out for Hajj or ‘Umrah. We said: "Should it so happen that we come into contact with one of the Prophet's Companions, we will ask him about what those people say about the predestination." Accidentally, we came across ‘Abdullāh ibn ‘Umar ibn al-Khattāb, while he was entering the mosque. My companion and I surrounded him, one of us on his right and the other on his left. I expected that my companion would authorize me to speak. I therefore said: "Abu ‘Abdur-Rahmān, there have appeared some people in our land who recite the Qur'an and pursue knowledge." After talking about their affairs, I added: "They claim that there is no such thing as the predestination, and that events are not predestined." He said: "If you happen to meet such people, tell them that I have nothing to do with them and they have nothing to do with me. By the One by Whom ‘Abdullāh ibn ‘Umar swears, if anyone of them had with him gold equal to Uhud and spent it (in charity), Allah would not accept it unless he believed in the predestination." [Narrated by Muslim in the introduction of his Sahīh (8) and Al-Ājurri in Ash-Sharī‘ah (2/851)]
Abu Hārūn al-Abali - one of the companions of Sahl ibn ‘Abdullāh, and he was a righteous man who used to recite the Qur’an to us in the grand mosque, reported: Sahl ibn ‘Abdullāh was asked about the predestination, and he said: "Belief in the predestination is an obligation, denying it is a disbelief, engaging in idle talk about it is a religious innovation, and keeping silent about it is Sunnah." [Sharh Usūl I‘tiqād Ahl As-Sunnah Wa Al-Jamā‘ah (4/786)]
Al-Hasan al-Basri said: "The Pen dried up, the decree was determined, and the predestination was accomplished by executing the book, believing the messengers, giving bliss to those who act rightly and fear Allah and misery to those who transgress and do wrong, and by granting Allah's protection to the believers and His disavowal to the polytheists." [Ash-Sharī‘ah for Al-Ājurri (2/881]
Ibn Battah al-‘Akburi said: "This is followed by belief in the predestination, with its pleasant and unpleasant aspects and its sweetness and bitterness. It is wholly determined by Allah, the Exalted, for His servants, and it happens exactly at the time He wills, without advancement or delay, according to His foreknowledge. And the belief that whatever befell a person would not have missed him and whatever missed a person would not have befallen him, and whatever happened earlier would not have come later, and whatever happened later would not have come earlier. Belief in this is a necessary duty and obligation imposed by Allah Almighty upon His servants. Whoever opposes this, departs from it, or casts doubt on it and does not affirm the predestination for Allah Almighty and attribute it to Him, or attribute the will to Him is the first step to infidelity (disbelief)." [Ash-Sharh Wa Al-Ibānah ‘Ala Usūl As-Sunnah Wa Ad-Diyānah, by Ibn Battah (213-216)]