"And prove the very truth he most abhorred"
Don Juan in Mozart's opera Don Giovanni, by Max Slevogt
Public DomainDon Juan in Mozart's opera Don Giovanni, by Max Slevogt - Credit: wikimedia commons

This is a reference to a line from Canto I of Byron’s poem Don Juan (1819-24):

 

I can't tell how, or why, or what suspicion

     Could enter into Don Alfonso's head;

But for a cavalier of his condition

     It surely was exceedingly ill-bred,

Without a word of previous admonition,

     To hold a levee round his lady's bed,

And summon lackeys, arm'd with fire and sword,

To prove himself the thing he most abhorr'd.