Sunan Abi Dawud 4608
سنن أبي داود#4608Sahih‘Abd Allah b. Mas’ud reported the Prophet (ﷺ) as saying:"Beware! The extremists perished," saying it three times
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Al-AlbaniSahih
Muhammad Muhyi Al-Din Abdul HamidSahih
Shuaib Al ArnautSahih
Zubair Ali ZaiSahih Muslim (2670)
In-book reference: 42:13