I think it behooves us to question what we accept as God's breath, God's word to the world, and then realize the canon arrived at man's election. That what many Christians today follow is a creed appointed by Constantine and that outlined belief in practice and thought.
If God speaks what power is vested in man to decide what should be heard?
Islam is a false faith. We know this. Muhammad was illiterate. He claimed to get the word of Allah through the emissary angel Gabriel and for many years on end.
Then Muhammad supposedly dictated what was imprinted into his memory by this angel to the scribe he entrusted to write it down.
If God wanted to speak to the world as a supreme being he would have served the purpose far better than choosing an illiterate to deliver the message.
And also, though some claim the culture is the excuse, God would have done well to choose someone who did not marry a little girl and represent himself as a prophet who was also a child rapist. This by the western standards at the very least and that culture that would later judge the man for his choices.
A prophet of a higher power is not credible when he's a low life.