"When 'Ali was in Yemen, he sent some gold that was still enclosed in rock to the Prophet ) said: 'Among the offspring of this man there will be people who will recite the Qur'an but it will not go beyond their throats, and they will go out of Islam as an arrow goes through the target. They will kill the Muslims and leave the idol-worshippers alone. If I live to see them, I will kill them as the killing of 'Ad.'"
Sunan an-Nasa'i Book 37, Hadith 136