—the very verse already cited, for He says:

“Say, ‘Tell me: if it is truly from Allah and you then deny it, who is more astray than one sunk in deep dissension?’” (Fussilat 41:52).

The implied pronoun in the verb “kana” (“if it is”) refers to something already understood. In other words, the verse is saying: Suppose the Qur’an is from Allah, and yet you reject it—who could be further astray than someone caught in such distant schism? On that assumption the disbeliever has opposed Allah and His Messenger, and no one is more misguided than a person embroiled in this kind of dissension, standing on one side while Allah and His Messenger stand on the other.

The Exalted likewise says:

“Say, ‘We believe in Allah and in what has been sent down to us, and in what was sent down to Abraham, Ishmael, Isaac, Jacob, and the Tribes; and in what was given to Moses and Jesus; and in what was given to the prophets from their Lord. We make no distinction between any of them, and to Him we submit.’ If they then believe in the like of what you believe, they are rightly guided; but if they turn away, they are only in schism. Allah will suffice you against them, for He is the All-Hearing, the All-Knowing.” (al-Baqarah 2:136).