Medieval polemicists coerced the Qur’an’s own terms into proofs of the Trinity

Evidence

The authentic Qur’anic objection to the doctrine of the Trinity does not normally appear in these examples of false-Augustinian temper, but a number of writers did seek to use arguments from the Qur’an which they felt Muslims would be bound to accept; this was done with more sympathy and with less, and both with, and without, the aid of the comparationes. It was held that the Qur’an itself admitted the truth of the Trinity. Oliver of Paderborn sought ground common to the two religions in terms like ‘breath of God’. As God is simple in nature and there is nothing in God which is not God, and (Christ) was conceived by the breath of God, it is evident that He is God; and the breath of God is nothing but the Holy Ghost, and the speech of God nothing else but the Word of God. — Norman Daniel, Islam and the West, 997