Huzaifa bin Yaman reported,

We were sitting with Umar when he asked, "Which of you remembers what the Messenger of Allah ﷺ said about the trial?"I said, "I do, exactly as he said it."He said, "You are bold about it indeed."I said, "The trial of a man in his family, his property, his children, and his neighbor is expiated by prayer, fasting, charity, enjoining good, and forbidding evil."He said, "That is not what I mean. Rather, I mean the trial that surges like the surging of the sea."I said, "You have no concern with that one, Commander of the Believers. Between you and it there is a closed door."He asked, "Will the door be broken or opened?"I said, "It will be broken."He said, "Then it will never be closed again."We asked, "Did Umar know what the door was?"He replied, "Yes, as surely as the night precedes the morning. I narrated to him a hadith that was not a fabrication."We were too apprehensive to ask Hudhayfah ourselves, so we instructed Masruq to ask him. He asked, and Hudhayfah said, "The door is Umar."In another narration, Hudhayfah added, "I heard the Messenger of Allah ﷺ say, 'Trials are presented to hearts like reeds woven into a mat, one by one. Whichever heart absorbs them, a black mark is placed upon it, and whichever heart rejects them, a white mark is placed upon it, until hearts become of two kinds. One is white like a smooth stone, which no trial will harm as long as the heavens and the earth endure. The other is black and ash-colored like an overturned vessel, recognizing no good and rejecting no evil, except what it has absorbed of its own desires.'"Hudhayfah said, "And I told him that between you and it there is a closed door which is about to be broken."Umar asked, "Will it be broken? May you have no father! Had it been opened, perhaps it could have been restored."I said, "No, rather it will be broken."And I told him that the door was a man who would be killed or who would die, a hadith that was not a fabrication.He said, meaning that this was reported from the Messenger of Allah ﷺ.

عن حذيفة قال

كنا جلوسا عند عمر فقال: أيكم يحفظ قول رسول الله ﷺ في الفتنة؟ قلت: أنا، كما قاله. قال: إنك عليه أو عليها لجريء، قلت: فتنة الرجل في أهله وماله وولده وجاره تكفرها الصلاة والصوم والصدقة والأمر والنهي، قال: ليس هذا أريد، ولكن الفتنة التي تموج كما يموج البحر، قال: ليس عليك منها بأس يا أمير المؤمنين، إن بينك وبينها بابا مغلقا، قال: أيكسر أم يفتح؟ قال: يكسر، قال: إذا لا يغلق أبدا، قلنا: أكان عمر يعلم الباب؟ قال: نعم، كما أن دون الغد الليلة، إني حدثته بحديث ليس بالأغاليط، فهبنا أن نسأل حذيفة، فأمرنا مسروقا، فسأله فقال: الباب عمر. وفي رواية زاد حذيفة وقال: سمعت رسول الله ﷺ يقول: تعرض الفتن على القلوب كالحصير عودا عودا، فأي قلب أشربها نكت فيه نكتة سوداء، وأي قلب أنكرها نكت فيه نكتة بيضاء، حتى تصير على قلبين، على أبيض مثل الصفا، فلا تضره فتنة ما دامت السماوات والأرض، والآخر أسود مربادا كالكوز مجخيا لا يعرف معروفا ولا ينكر منكرا، إلا ما أشرب من هواه. قال حذيفة: وحدثته أن بينك وبينها بابا مغلقا، يوشك أن يكسر، قال عمر: أكسرا لا أبا لك! فلو أنه فتح لعله كان يعاد، قلت: لا بل يكسر، وحدثته أن ذلك الباب رجل يقتل أو يموت، حديثا ليس بالأغاليط. قال: يعني أنه عن رسول الله ﷺ.