The Messenger of Allah ﷺ said, "There will appear at the end of time a people, young in age and foolish in mind. They will speak the finest words ever uttered by people, yet their recitation of the Quran 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 killing them carries a reward with Allah for the one who slays them."
حدثنا أبو بكر بن أبي شيبة وعبد الله بن عامر بن زرارة قالا حدثنا أبو بكر بن عياش عن عاصم عن زر
قال رسول الله ﷺ يخرج في آخر الزمان قوم أحداث الأسنان سفهاء الأحلام يقولون من خير قول الناس يقرءون القرآن لا يجاوز تراقيهم يمرقون من الإسلام كما يمرق السهم من الرمية فمن لقيهم فليقتلهم فإن قتلهم أجر عند الله لمن قتلهم
[Sahih] Reported by Tirmidhi, Fitan, chapter on what has been said about the description of the deviant sect, no. 2188, from the hadith of Abu Bakr bin Ayyash, through him, and he said, hasan sahih. The hadith has many corroborating narrations in Bukhari and Muslim and others.