Wrap your head around this; Satan is no fool, he takes truth, and grows it with pagans...he knows this will make you step back, and doubt Gods truth.
As to the Jews, "Why did God make them his people?" If he had taken the best people to follow him, Satan would have said, "Only the beset would follow you." So God took the worst to prove people would follow him out of love." Here is what God says about the Jews, "They are the most hard headed, and hard hearted of all the people of the earth." In other words he took the worst to prove his point.