I would prefer to read MACBETH more as a tragedy of character than as a tragedy of any dark fatality. Even if we like to assign the tragedy of Macbeth to Fate, that fatality lies in his character. The three witches may appear as the 'fate sisters', but Macbeth's 'vaulting ambition' which leads him to his downfall was already present deep in his mind. His immediate responses, especially his asides in act1 sc.3, suggest this evil seed in Macbeth. If we hold Lady Macbeth responsible for Macbeth's downfall, we should remember how Macbeth sends letter to his wife briefing her all about the witches and the good chance of their prophecy about his kingship come true. The conflict between his ambition and his conscience--the 'foul' and the 'fair' battling each other in him-- leads to a series of crimes, to his death in the hands of Macduff. Shakespeare dramatises the story of a moral-psychological conflict, a morality play to highlight the Renaissance contradictions in his protagonist.
Shakespeare was a staunch catholic and his characters also reflects his thoughts.Macbeth is a symbol of vaulting ambition, which is a tragic flaw.For every sinner there is a punishment .For Macbeth ,his punishment comes in the form of the witches and he does and believes everything they said.Fate was strong when it made Duncan's son escape from the murder scene.Fate also was strong when it send Macduff away when his family was brutally killed by Macbeth"s men.It was much too fatal when Macbeth failed to know that Macduff was not borne off his mother but was ripped off.Macbeth's life tells how little we know,though we boast to know everything.