And whoever professes the doctrine of universal ḥulūl and ittiḥād (indwelling and union), his misguidance is even more far-reaching than that of the Christians. The same applies to anyone who asserts that the souls of the children of Adam—or their deeds, their speech, their voices, the very ink of their codices, or anything of that sort—are eternal; in such a claim there is a branch of the Christians’ belief.

Thus, by grasping the true nature of the Christian religion and the futility of its creed, one can expose the falsity of every heretical or innovative statement that resembles it. When the light of faith and the Quran appears, Allah causes by it whatever contradicts that light to vanish, just as He, Most High, says:

“Say: ‘Truth has come, and falsehood has vanished. Surely falsehood is ever bound to perish.’” [Al-Isrāʾ, 81].

Allah—glorified and exalted—has also laid bare the virtues and beauties of the truth, granting it the triumph it deserves.

[Reason for Compiling the Book]
Among the factors that led to the support and prominence of the religion was the arrival of a treatise from Cyprus. The treatise advanced proofs for the Christian faith—textual and rational alike—of the sort long employed by their theologians and the distinguished figures of their community, both past and present. This made it necessary for us to compose a reply that would deliver decisive judgment, clarifying error from correctness, so that people of sound intellect might benefit and so that the Balance and the Book with which Allah sent His messengers would become manifest.