Sahih al-Bukhari Book 61, Hadith 151
I said, "O Allah's Messenger (ﷺ)! I hear many narrations from you but I forget them." He said, "Spread your covering sheet." I spread my sheet and he moved both his hands as if scooping something and emptied them in the sheet and said, "Wrap it." I wrapped it round my body, and since then I have never forgotten.
Allah's Messenger (ﷺ) reached Khaibar in the early morning and the people of Khaibar came out with their spades, and when they saw the Prophet (ﷺ) they said, "Muhammad and his army!" and returned hurriedly to take refuge in the fort. The Prophet (ﷺ) raised his hands and said, "Allah is Greater! Khaibar is ruined ! If we approach a nation, then miserable is the morning of those who are warned."
"Allah's Messenger (ﷺ) said, "A time will come upon the people, when a group of people will wage a holy war and it will be said, 'Is there amongst you anyone who has accompanied Allah's Messenger (ﷺ)?' They will say, 'Yes.' And so victory will be bestowed on them. Then a time will come upon the people when a group of people will wage a holy war, and it will be said, "Is there amongst you anynone who has accompanied the companions of Allah's Messenger (ﷺ)?' They will say, 'Yes.' And so victory will be bestowed on them. Then a time will come upon the people when a group of people will wage a holy war, and it will be said, "Is there amongst you anyone who has been in the company of the companions of the companions of Allah's Messenger (ﷺ) ?' They will say, 'Yes.' And victory will be bestowed on them."