Musnad Abu Ya'la al-Mawsili 3:98

Ali bin Abi Talib narrated that the Messenger of Allah (may Allah bless him and grant him peace) said: "A people will pass through Islam just as an arrow passes through the game. They recite the Quran, but it does not go beyond their throats. Blessed is he who kills them and whom they kill. Their sign is a man with a deformed hand."