Come, you spirits that tend on mortal thoughts, unsex me here

To remember this quote use the following mnemonic.

Come you spirits, that tend to hold on to my thoughts.

Undo my sex, here and now and change me into a man.

"Come, you spirits that tend on mortal thoughts, unsex me here." Act 1, scene 5, line 39.

Meaning 

• A plea from Lady Macbeth to supernatural beings to strip her of her feminine nature and make her more like a man. Remove her of the lady-like features she owns and fill her with manly strength that will allow her to commit the cruel and unspeakable act of killing King Duncan.

Exam Advice

• Theme of Ambition and Ruthlessness - Lady Macbeth wants to remove all pity and conscience so she can help Macbeth seize the crown by force.

• Theme of Gender and Strength -  She believes that femininity is linked to weakness, so she wants to reject her womanhood to become stronger and more violent.

• Theme of Supernatural - By calling on spirits, she shows her willingness to embrace dark forces to achieve her goals. 

• Theme of Moral Corruption - This moment reveals her unnatural desire to become inhuman so she can commit evil without guilt.