“O Amirul Muminin, indeed between you and it is a closed door.”
Shafeeq Ibn Salamah reported that Hudhaifah Ibn Al-Yaman [Allah be pleased with him] said, “As we were seated in the company of ‘Umar Ibn Al-Khattab [Allah be pleased with him], he said, “Who among you has memorised that Hadith of Messenger of Allah [Sallallahu ‘alayhi wasallam] regarding the fitnah(tribulation)?” I said, “I”. He said, “Tell it, you are indeed bold.”
I(Hudhaifah) said, “He[Sallallahu ‘alayhi wasallam] mentioned the Fitnah of a man in his family, his wealth, his self, his child, and his neighbour – Which are all expiated for by prayer, charity, the ordering of good, and the ordering of good, and the forbidding of evil.”
He(‘Umar) said, “That is not what I meant; I am referring to (the fitnah) which will become agitated like the agitation of the sea (ie when people will become submersed in discord).”
I(Hudhaifah) Said, “O Amirul Muminin, Indeed between you and it is a closed door.”
He(‘Umar) said, “Woe unto you! Will the door be opened or will it break?”
I(Hudhaifah) said, “Rather, it will break.”
He(‘Umar) said, “Then it will never be closed again.”
I(Hudhaifah) said, “Indeed.””
Shafeeq Ibn Salamah Said, ” We said to Hudhaifah, “It is as if ‘Umar knows who that door is? “”
Hudhaifah answered, “Yes, I related to him a hadith that was not false (not false because it was spoken by the Prophet[Sallallahu ‘alayhi wasallam] who spoke not from desire, but from revelation).”
Shafeeq later said, “We were afraid to ask to ask Hudhaifah[Allah be pleased with him] who the door was, so we asked Masrooq to ask.”
Hudhaifah answered, “‘Umar [Allah be pleased with him]”
And this is exactly what occured.
After ‘Umar[Allah be pleased with him] was killed in the year 23H, people became engulfed in trials; ‘Umar’s death was what led to the spreading of those trials.
[Al Bidayah Wan Nihayah by Imam Ibn Kathir]