And if you are in doubt concerning what We have revealed, that is, [doubt concerning] Our revelation to Muḥammad and thus doubt the truthfulness of his prophethood, then weigh up your human forces and summon your analogy-strong minds, veiled [as they are] from the light of guidance, and your thoughts, skilful [as they are] in putting together speech and arranging meanings, being as you are of your own, children of your species: would you be able to produce a sūra, that is, a segment of speech like it? [to Our servant, then bring a sūra like it; and call your witnesses besides God] if you are truthful, in attributing it to Muḥammad.