Tafsir of At-Tur 52:34

Let them bring a discourse like it (meaning a discourse analogous to the Quran in the qualities through which it is unique, both in terms of its composition and its meaning), if they are truthful (in what they claim; for their truthfulness in that requires their ability to produce its like, by virtue of their shared humanity and Arabic language with him, peace and blessings be upon him, along with their long-standing practice in orations and poetry, their extensive engagement with the methods of prose and verse, and their exaggeration in memorizing historical events and battles. There is no doubt that the ability to do something is among the requirements for bringing it forth and among the motives for demanding it. Thus, the speech is a refutation of the claims mentioned regarding him, peace and blessings be upon him, and the Quran by way of challenge. When they were challenged and were unable, it became known that what they said was refuted and the claim [of the Prophet] was valid. It is also possible that it is a refutation of their specific claim of fabrication, for other claims that preceded it, even [the accusation of] soothsaying, are—as is not hidden—more obviously corrupt than it. Nevertheless, when the corruption of their claim of fabrication becomes apparent, the corruption of the others becomes apparent by way of necessity).