how can we feel sympathy for macbeth even though he has been described as "a hell hound" and "a butcher" ..please explain with few examples of quotes

The sympathy comes from Macbeth knowing what he has become.  In Act 5, scene 3, Macbeth laments in his speech, "...my way of life is fall'n into the sere, the yellow leaf;..." that he realizes his life has taken a bad turn, he has little to look forward to, he has no friends, etc.  Two scenes later, in scene 5, in his famous, "Tomorrow, and tomorrow, and tomorrow..." speech, he again tells us that he knows he's been a fool.  We see him fall prey to the witches and their misleading prophecies.  Overall though, I believe we can sympathize with him because we can see bits of ourselves and our own ambitions in him.