Who here was around 1600 years ago when the Qur'an was delivered by Allah to his prophet? Or the bible delivered by god? How do we know that these events actually happened apart from blind faith?

Unless we have concrete evidence that these events took place no-one can say that the Qur'an is more than a work of fiction with any certainty.

The Qur'an itself is not proof of this, just as any of us would have trouble believing a person who arrived tomorrow carrying a book that claimed he/she was the almighty and powerful creator, we can't all just take the Qur'an's word for it.