Rib'i bin Hirash said: I performed Hajj with Hudhayfah (may Allah be pleased with him), and he sat with Umar bin al-Khattab (may Allah be pleased with him). Umar (may Allah be pleased with him) said: O Companions of Muhammad (peace and blessings be upon him)! Which of you has heard the Messenger of Allah (peace and blessings be upon him) mention the fitnah (tribulation)? Hudhayfah said: I have. Umar said: You are very bold. Hudhayfah said: Bolder than me is the one who conceals knowledge. Umar asked: Then how did you hear it? Hudhayfah said: I heard the Messenger of Allah (peace and blessings be upon him) say: "In a man's wealth there is a fitnah, and in his wife and children there is a fitnah." Umar said: I did not ask about his own particular fitnah. Hudhayfah said: I heard the Messenger of Allah (peace and blessings be upon him) say: "After me, tribulations will come upon you like the waves of the sea pushing one another." Umar raised his hand and said: O Allah, do not let me live to see it. Hudhayfah said: O Commander of the Believers, do not fear; between you and that tribulation there stands a closed door. Umar asked: Will that door be opened or will it be broken? Hudhayfah said: It will be broken, and then it will not be closed until the Day of Resurrection. Umar said: Then that is a great evil for this Ummah.
Hadith Referenceالمعجم الكبير للطبراني / باب الحاء / 3011