Sahih al-Bukhari 5301
صحيح البخاري#5301SahihNarrated Sahl bin Sa`d As-Sa`idi:(a companion of Allah's Messenger (ﷺ)) Allah's Messenger (ﷺ), holding out his middle and index fingers, said, "My advent and the Hour's are like this (or like these)," namely, the period between his era and the Hour is like the distance between those two fingers, i.e., very short
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 68:50