All that glitters is not gold

I'm the Prince of Morocco. I'm seriously into bling. Fine jewelry and gold? Yes, please. I've got dolla-dolla-ducats comin' out my ears. And you know what I think? Let me tell you.

O hell! what have we here?
A carrion Death, within whose empty eye
There is a written scroll! I'll read the writing.

Reads

All that glitters is not gold;
Often have you heard that told:
Many a man his life hath sold
But my outside to behold:
Gilded tombs do worms enfold.
Had you been as wise as bold,
Young in limbs, in judgment old,
Your answer had not been inscroll'd:
Fare you well; your suit is cold.
Cold, indeed; and labour lost:
Then, farewell, heat, and welcome, frost!
Portia, adieu. I have too grieved a heart
To take a tedious leave: thus losers part. (2.7.62-77)

Who Said It and Where

Poor Portia. Even though her father is dead, the guy still manages to control her life from the grave. See, in his will, Portia's father said that her husband would be determined according to a lottery (yeah, we know, it's more like a contest). Since Portia is rich, smart, and beautiful, men travel from all over the world for a chance to marry the heiress. (We'd say that's a gross, outdated practice, but it sounds an awful lot like a certain TV show we love to loathe, so we'll keep our mouths shut.)

Here's the deal. A suitor is given the option of choosing one of three caskets: gold, silver, and lead. If he guesses correctly, he gets Portia and all her money. If he chooses incorrectly, he has to leave Belmont immediately and can never, ever marry. Like ever. Apparently, Portia's dad reasoned that the man who chooses the correct casket (which holds a picture of Portia inside) will be the right man for our girl.

Now that he knows all the rules, the Prince of Morocco sets about choosing a chest. He goes over each of the inscriptions and reasons to himself. The lead chest asks the man who chooses it to risk everything; the Prince decides he wouldn't risk everything, or anything really, for plain old lead.

Then he decides the silver chest has better promise, as it says he'll get what he deserves in choosing it. The Prince declares that he has to weigh what he deserves carefully, and he determines that in birth, fortunes, grace, and stature, he deserves Portia. Oh, and because of how much he loves her. Yeah… that.

He says he could be happy with the silver chest, but he checks out the gold one anyway, as it promises what many men desire. It seems all men desire Portia, as they're coming from every corner of the earth to woo her.

Welp, it's time for the Prince to choose. He decides lead is too worthless, and silver is of less worth than gold, so gold is the only thing worthy enough to hold Portia's picture.
When the Prince opens the golden casket, he finds a picture of a skull and crossbones and a scroll beginning with the famous words, "All that glisters [glitters] is not gold." Whoops.

And so, our tall, dark, handsome and rich Prince is condemned to a life of solitude. So what does he do? He get's the heck out of dodge, and quick. Portia gladly lets him go. Whew. Crisis averted.