dear mP...
the koran is only part of the history of the islamic movement...there are also the hadiths, which are more lengthy. they go into the details of what happened in mohammad's campaigns as well as the manipulative nature of his rise to power.
God chose israel as a people. in those days, as in these days, there were wars between nations. The difference between these nations was the fact that God wanted israel to succeed in order that His Christ would be delivered through the nation He chose...to be a blessing to all who would choose Him.
There is no other people nation that God chose.
The thing about king david is that he REPENTED of his sins. God always accepts people who have repentance in their heart.
love michelle