* Create a sense of atmosphere: The repetition of certain words and phrases, such as "blood" and "murder," helps to create a dark and foreboding atmosphere that reflects the play's themes of violence and guilt.
* Emphasize important ideas: Shakespeare often repeats key ideas throughout the play to emphasize their importance. For example, the repetition of the phrase "fair is foul, and foul is fair" highlights the play's exploration of the themes of good and evil.
* Develop character: Shakespeare uses repetition to develop the characters of Macbeth and Lady Macbeth. For example, Macbeth's repeated use of the word "blood" reflects his growing obsession with violence, while Lady Macbeth's repeated use of the word "ambition" reflects her driving desire for power.
* Create a sense of suspense: Shakespeare uses repetition to create a sense of suspense and tension in the play. For example, the repetition of the knocking sound at the door in Act 2, Scene 2, builds suspense and anticipation for what is to come.
* Reveal the characters' inner thoughts: Shakespeare uses repetition to reveal the characters' inner thoughts and feelings. For example, Macbeth's repeated use of the word "coward" reflects his inner fears and insecurities, while Lady Macbeth's repeated use of the word "unsex me" reflects her desire to become more ruthless and masculine.
Overall, the repetition in Macbeth has a variety of effects on the play. It creates a sense of atmosphere, emphasizes important ideas, develops character, creates a sense of suspense, and reveals the characters' inner thoughts. By using repetition, Shakespeare is able to create a rich and complex play that explores the themes of violence, guilt, and ambition.