I only have one thing to add...
The Quran does state that non-Muslims will burn in hell for eternity.
In order to be a "Believer" one must not only believe in Allah but they must also believe in Muhammad as the prophet of Allah.
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YUSUFALI: Those who reject (Truth), among the People of the Book and among the Polytheists, will be in Hell-Fire, to dwell therein (for aye). They are the worst of creatures.
(What do you think the "Truth" is here?) Also check out Quran 46:29-35.
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YUSUFALI: Say: "If ye do love Allah, Follow me: Allah will love you and forgive you your sins: For Allah is Oft-Forgiving, Most Merciful."
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YUSUFALI: Say: "Obey Allah and His Messenger": But if they turn back, Allah loveth not those who reject Faith.
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YUSUFALI: If anyone desires a religion other than Islam (submission to Allah), never will it be accepted of him; and in the Hereafter He will be in the ranks of those who have lost (All spiritual good).
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YUSUFALI: Those who deny Allah and His messengers, and (those who) wish to separate Allah from His messengers, saying: "We believe in some but reject others": And (those who) wish to take a course midway,-
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YUSUFALI: They are in truth (equally) unbelievers; and we have prepared for unbelievers a humiliating punishment.
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YUSUFALI: To those who believe in Allah and His messengers and make no distinction between any of the messengers, we shall soon give their (due) rewards: for Allah is Oft-forgiving, Most Merciful.
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YUSUFALI: O ye who believe! take not the Jews and the Christians for your friends and protectors: They are but friends and protectors to each other. And he amongst you that turns to them (for friendship) is of them. Verily Allah guideth not a people unjust.
I think that's enough for now.