Why did God create Satan?

This question was recently asked by one of my students in class. Many people also ask that questions and wonder why. 

Because God is love. God created him whom we now call Satan as a being of very exalted glory. A hint of what Satan was as originally created we get in Ezekiel 28. Because he was a being of such exalted glory he was a mortal being, that is , a being with the power of choosing good or evil. He seems to have been the one that led the worship of the universe. But ambition entered his heart. he seems to have tried to direct to himself what properly belonged to God, and thus he fell. The Devil is not a hideous-looking being with horns and hoofs, but a being of lofty intellogence who has turned his mighty powers to wrong and has thus become the great enemy of God and man.