Bukhari

Narrated Sahl bin Sa`d: I saw Allah's Messenger pointing with his index and middle fingers, saying. "The time of my Advent and the Hour are like these two fingers." The Great Catastrophe will overwhelm everything.

Mujahid said that by «الآية الكبرى‏» is meant the staff of Musa (Moses), peace be upon him, and his hand. Both «عظاما ناخرة» and «ناخرة» have been recited, just as «طامع», «طمع», «باخل», and «بخيل». And some have said there is a difference between «نخرة» and «ناخرة». «نخرة» refers to a decayed bone, and «ناخرة» is a hollow bone which, when air passes through it, produces a sound. And Ibn Abbas, may Allah be pleased with them both, said «حافرة‏» means our condition in this worldly (life). Others have said «أيان مرساها‏» means, "What is its end?" This word is derived from «مرسى السفينة», meaning the place where a boat finally comes to rest.