Nothing takes place in the world except by the Will of Allah, and nothing will hit the slave, whether good or evil, health or sickness, poverty or richness, or other than that, except by the Will of Allah, and nothing that Allah Willed to hit the slave will miss him. It came that the Prophet taught one of his daughters to say:
مَا شَاءَ اللهُ كَانَ وَمَا لم يَشَأْ لم يَكُن
[which means] “Whatever Allah Willed to be shall be, and whatever Allah did not Will to be shall not be.” This is narrated by Abu Dawud in his book As-Sunan. Then it became tawatur from there and spread abundantly among the individuals of the nation.
Al-Bayhaqiyy narrated from our master ^Aliyy that he said: “Certainly, the iman will not be pure in the heart of one of you until he is absolutely certain that whatever hit him was not going to miss him, and whatever missed him was not going to hit him, and he confesses about the Qadar completely.” This means it is not permissible to believe in some of the Qadar and to disbelieve in some of it.
Al-Bayhaqiyy also narrated with an authentic chain of narration that ^Umar Ibnul-Khattab was in Al-Jabiyah, which is an area in Ash-Sham, when he stood to give a speech. He praised Allah and then said, “Whomever Allah Guided, then there will be no one to misguide him, and whomever Allah Misguided, then there will be no one to guide him.” In the audience was a non-Arab blasphemer, i.e., he was among the people of adh-dhimmah.[1] He said in his own language, “Certainly Allah does not misguide anyone.” Then ^Umar said to the translator, “What is he saying?” The translator said, “He is saying that Allah does not misguide anyone.” Then ^Umar said, “You lied, O enemy of Allah. And had it not been that you are among the people of adh-dhimmah I would have beheaded you. He is the one who Misguided you and He is the One who will Put you in Hell if He willed.”
[1] A non-Muslim subject of the Muslim state.