Musnad Abu Ya'la al-Mawsili 115:276

Ahmad ibn Ibrahim al-Dawraqi narrated to us, Mubashir narrated to us, from al-Awza’i, from Qatadah, from Anas and Abu Sa’id al-Khudri, that the Messenger of Allah (ﷺ) said: "There will be in my nation disagreement and division. They will speak well and act poorly. They will recite the Quran, but it will not pass beyond their collarbones. They will pass through the religion just as an arrow passes through the game, then they will not return to it until the arrow returns to its notch. They are the worst of creation and creatures. Glad tidings to whoever kills them, and glad tidings to whoever they kill. They call to the Book of Allah, while they have no part in it. Whoever fights them is closer to Allah than they are." They said: "O Messenger of Allah, what is their sign?" He said: "Shaving [the head]."