Your Muslim friend

 Two questions for your Muslim friend (and I mean friend: this is to be a fruitful and friendly conversation):

1. How do you know who is a prophet?

2. How can you tell if a document is from God?

The discussion:

1. Mohammad is claimed to be a prophet, because he said so. The biblical prophets claim to speak for God in the public sphere, not hidden in a cave; they make predictions; the predictions come about.

Mohammad was an acquitistive war lord; the prophets of God in the Bible were far from the 'great', but humble and despised; yet they spoke against the powers of the day to their own detriment and had a massive effect in history.

2. The document records the events of people, words of God, and unfolding of history in public. For all to see, for others to debate and comment on. The Q by contrast was compiled from 'narrators' 200 years after it was claimed to be dictated (no one else was there), and Uthman destroyed the written parts he didn't like.