Thou art the best o’ the cut-throats: yet he’s good
That did the like for Fleance: if thou didst it,
Thou art the nonpareil.

– William Shakespeare

Macbeth, Act 3, Scene 4. Macbeth compliments one of his thugs on being the best of the murderers on learning that he cut Banquo’s throat. Macbeth shows no remorse for arranging to have his best friend killed – the ultimate betrayal. He goes on to tell the murderer that whoever can cut the young Fleance’s throat is a cutthroat without parallel. This tells us how important it is to Macbeth that Fleance dies.