Act III, Scene II. Belmont. A Room in Portia’s House.

“So may the outward shows be least themselves:
The world is still deceived with ornament…
How many cowards, whose hearts are all as false
As stairs of sand wear yet upon their chins
The beards of Hercules and frowning Mars

Who, inwards searched, have livers white as milk;
And these assume but valour’s excrement to render them redoubted!”

— The Merchant of Venice, William Shakespeare [Full play online]