Sahih al-Bukhari 5057
صحيح البخاري#5057SahihNarrated `Ali:I heard the Prophet (ﷺ) saying, "In the last days (of the world) there will appear young people with foolish thoughts and ideas. They will give good talks, but they will go out of Islam as an arrow goes out of its game, their faith will not exceed their throats. So, wherever you find them, kill them, for there will be a reward for their killers on the Day of Resurrection
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: 66:82