What is the difference in Macbeth's character before and after ?

Before the witches' prophecy Macbeth is a strong and able warrior. He is loyal, discerning, and places his moral beliefs above all else. The witches' prophecy drives his ambition, and although this is not to say he wasn't always amibitious, we see a new man with no scruples. Macbeth becomes a person he would hitherto have despised..... the guilt drives him to madness.