The Messenger of Allah ﷺ said, "In the latter times, there will emerge a people who are young in age and foolish in mind. They will speak the words of the best of people, reciting the Quran, yet it will not pass beyond their throats. They will pass through Islam as an arrow passes through its target. Whoever encounters them should kill them, for whoever kills them will have a reward with Allah."
قال رسول الله ﷺ: يخرج في آخر الزمان قوم أحداث الأسنان، سفهاء الأحلام، يقولون من قول خير الناس، يقرؤون القرآن لا يجاوز تراقيهم، يمرقون من الإسلام كما يمرق السهم من الرمية، فمن لقيهم فليقتلهم، فإن قتلهم أجر عند الله لمن قتلهم.
This was narrated by Tirmidhi (2188), Ibn Majah (168), and Ahmad (3831), all of them through the route of Abu Bakr bin Ayyash, from Asim, from Zirr (that is, Ibn Hubaysh), from Abdullah bin Masud, and he related it. Its chain of transmission is hasan because of Abu Bakr bin Ayyash and Asim, who is Ibn Abu Najud, both of whom make a hadith hasan.Tirmidhi said, "This is a hasan sahih hadith."