Günter Lüling

"The text of the Koran as transmitted by Muslim Orthodoxy contains, hidden behind it as a ground layer and considerably scattered throughout it (together about one-third of the whole Koran text), an originally pre- Islamic Christian text.” Earlier Qur’anic scholars such as Alois Sprenger and Tor Andrae have also identified a Christian substratum."

"Lüling sees traces of the Christian controversies over the nature of Christ in the Qur’an’s denunciations of those who associate partners with Allah. Lüling sees the Muslim charge that the pagan Quraysh of Mecca were mushrikun, those who associated others with Allah in worship, as an indication that they had actually converted to orthodox Trinitarian Christianity, thereby reinforcing their rejection of Islam’s hardline monotheism and rejection of Christ’s divinity. As the Islamic faith began to develop as a distinct religion, it decisively rejected this faith in Christ and reinterpreted the Qur’an to fit its developing new theology. The hanifs, who were overwhelmed by the coming of Islam and its success, were the last remnants of those who held to creedally vague monotheism."