In Act 2, Scene 7, the prince of Morocco chooses the golden casket for he truly believes that Portia's image is contained therein. He says:
But here an angel in a golden bed
Lies all within. Deliver me the key:
Here do I choose, and thrive I as I may!
He first refuses the lead casket because he believes, in terms of its inscription, that the fact that the man who chooses it should hazard all he has is not a worthwhile exercise. Lead has no value and the other two metals would be much more rewarding choices, since they are more valuable. He also states that it is gross to even think that Portia's image would be immured in lead, for it is such a base metal.
He expresses similar sentiments with regard to the silver casket and says that the promise stated by the inscription that the one who chooses it shall get as much as he deserves, means that he deserves Portia. He is her equal in birth, rank, title and wealth, but he wants more than just those. He also deserves her love. He is suggesting that if he should stop choosing and decide on the silver casket, he might not get anything. Added to that, he also sees silver as unworthy when it is compared to gold. It is worth ten times less and it would be a sin and an insult if he should choose it, and, therefore, he decides to give it a miss.
In Scene 9, the Prince of Arragon states that he will assume nothing, but he chooses the silver casket because he agrees with the inscription that, 'Who chooseth me shall get as much as he deserves.' Prior to making his choice, the prince goes into a lengthy speech about the merit of one getting 'as much as he deserves.' It is as if he is giving a sermon about the value of integrity and honor.
He juxtaposes these with corruption, stating that if every person should get what he deserves, many would stand naked, for they would have acquired whatever they have either by deceitful means or favor. Although he is uncertain, he must somehow believe that he deserves Portia and, therefore, chooses the silver casket.
The prince displays his arrogance when he rejects the lead casket because it requires one 'to give and hazard all he hath.' He quips that Portia 'shall look fairer' before he would hazard anything. This may mean that she should either be more beautiful or have a lighter complexion. Whichever meaning one chooses, his remark is clearly an insult.
He refuses the gold casket because he does not want to be associated with what he calls 'the fool multitude' who tend to be impressed by the glitter and not what is truly inside. In a further display of supercilious pride, he states:
I will not choose what many men desire,
Because I will not jump with common spirits
And rank me with the barbarous multitudes.
He certainly has a very high opinion of himself. His reference to the common folk as 'barbarous multitudes' is an obvious indication that he ranks himself higher than everyone else.
In both these instances, the princes exhibit a haughtiness that Portia would well do without. Fortunately for her, both are unsuccessful and she, in both instances, expresses relief when they fail.