This Qur'an is not such as can be produced by other than Allah... ― wherein there is no doubt from the Lord of the Worlds.

This Qur'an is not such as can be produced by other than Allah; on the contrary it is a confirmation of (revelations) that went before it, and a fuller explanation of the Book― wherein there is no doubt from the Lord of the Worlds. (37) Or do they say "He forged it"? Say: "Bring then a Surah like unto it, and call (to your aid) anyone you can, besides Allah, if it be ye speak the truth!" (38)

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Quran: Chapter Yunus (10) - Verses 37-38