Final answer:
The phrase from Macbeth advises appearing innocent like a flower while harboring deceit, reflecting the theme of appearance versus reality in Shakespeare's work and Lady Macbeth's manipulative tactics.
Step-by-step explanation:
The line 'Look like th' innocent flower, But be the serpent under 't' from Macbeth (Act 1, Scene 5) advises to appear innocent and harmless like a flower while hiding malevolent intentions, akin to a serpent lying in wait. This theme of appearance versus reality is a common motif in Shakespeare's works, highlighting the duplicity of human nature and the complexity of social interactions. The quote epitomizes the deceptive strategies employed by Lady Macbeth as she urges her husband to disguise his true ambitions and murderous intentions.