Surah 6

Surah 6:93

"Who is more evil than the one who forges a lie against God, or says, ‘I am inspired,’ when he is not inspired at all, or the one who says, ‘I will send down the equivalent of what God has sent down’? If (only) you could see when the evildoers are in the throes of death, and the angels are stretching out their hands (saying): ‘Out with yourselves! Today you are repaid (with) the punishment of humiliation because you spoke about God (something) other than the truth, and (because) you behaved arrogantly toward His signs.’"

6.93 – Who is more evil than the one who... says, “I am inspired,” when he is not inspired at all... ?
The questions in this verse are indeed important for non-Muslim readers. Were the contents of the Quran truly “sent down”? Was the reciter of these verses “inspired”? These questions also bring to mind the prophetic test found in Deuteronomy 18:20: “But a prophet who presumes to speak in my name anything I have not commanded him to say...”

- from The Quran with Christian Commentary: A Guide to Understanding the Scripture of Islam