Which theme is used in this excerpt from act I of Shakespeare’s Macbeth?

LADY MACBETH:
O, never
Shall sun that morrow see!
Your face, my thane, is as a book where men
May read strange matters:—to beguile the time,
Look like the time; bear welcome in your eye,
Your hand, your tongue: look like the innocent flower,
But be the serpent under't,