Musnad Ahmad 1113:1

Harun narrated to us, Abdullah bin Wahb narrated to us, Abu Sakhr informed me, from Abdullah bin Mu'tab bin Abi Burdah al-Zufari, from his father, from his grandfather, who said: I heard the Messenger of Allah, peace and blessings of Allah be upon him, saying: "A man will emerge from the two Kahins (the two priests/soothsayers) who will study the Quran in a way of studying that no one who comes after him will study it."