We were with Umar when he said, "We have been forbidden from excessive formality."
كنا عند عمر فقال: نهينا عن التكلف.
Bukhari narrated it in the Book of Holding Fast (7293) from Sulayman bin Harb, who said, Hammad bin Zayd narrated to us, from Thabit, from Anas, and he mentioned it.And in Sunan Darimi (123), from Muslim bin Ibrahim, who said, Hammad bin Zayd Minqari narrated to us, who said, my father narrated to us, who said, a man once came to Ibn Umar and asked him about something, I do not know what it was. Ibn Umar said to him, "Do not ask about what has not happened, for I heard Umar bin Khattab curse whoever asks about what has not happened." Its chain is hasan. Yazid Minqari is Yazid bin Muslim. Ibn Hibban mentioned him in Thiqat (5/545), and no one else authenticated him, except that he has a corroborating narration with Abu Khaythama in Ilm (144), and Ibn Abdul-Barr in Jami Bayan Ilm (1820), and others.And from Tawus, who said, Umar said on the pulpit, "I solemnly adjure, by Allah, any man who asks about what has not happened, for Allah has already made clear what will happen." Darimi narrated it in his Sunan (126), and Bayhaqi in Madkhal (293), and Ibn Abdul-Barr in Jami Bayan Ilm (1807, 1808), and Khatib in Faqih wal-Mutafaqqih (7/2), all of them from the hadith of Sufyan, from Amr bin Dinar, from Tawus, mentioning something similar.In the wording of Khatib, "I solemnly adjure you not to ask us about what has not happened, for we have enough to occupy us in what has already happened." And he used to say, "Beware of this contentious disputation, for whenever it arises, Allah sends someone to settle it or explain it." Bayhaqi narrated it in Madkhal (294), and its chain is hasan.Bayhaqi, may Allah have mercy on him, said, "The early generations disliked that common people should ask about what has not happened, since no book, nor sunnah, nor consensus, nor narration has given a ruling on it for them to act upon should it occur. And they disliked that the one asked should exercise independent reasoning about it before it occurs, because independent reasoning is only permitted out of necessity, and there is no necessity before the event takes place. So their reasoning should be considered at the time the event occurs, and whatever reasoning was done beforehand will not suffice them." See Madkhal (286).