Inquiry trumps faith.
If the people of this religion are asked about
the proof for the soundness of their religion, they flare up, get angry and spill the blood of whoever confronts them with this question. They forbid rational speculation, and strive
to kill their adversaries. This is why truth became thoroughly silenced and concealed.
Lack of empirical evidence
Discovery trumps revelation.
You claim that the evidentiary miracle
is present and available, namely, the Koran.
You say "Whomever denies it, let him produce
a similar one." Indeed, we shall produce
a thousand similar, from the works
of rhetoricians, eloquent speakers and valiant poets, which are more appropriately phrased and state the issues more succinctly.
Reason trumps custom.
You are talking about a work which recounts ancient myths, and which at the same time
is full of contradictions and does not contain
any useful information or explanation.
Then you say "Produce something like it!"
The argument from evil
Autonomy trumps piety.
On what ground do you deem it necessary
that God should single out certain individuals, that he should set them up above other people, that he should appoint them to be the people's guides, and make people dependent upon them?