Shylock thinks he has won the day and approaches Antonio with a knife to carve out his pound of flesh, but Portia continues:
Tarry a little; there is something else.
This bond doth give thee here no jot of blood;
The words expressly are 'a pound of flesh:'
Take then thy bond, take thou thy pound of flesh;
But, in the cutting it, if thou dost shed
One drop of Christian blood, thy lands and goods
Are, by the laws of Venice, confiscate
Unto the state of Venice.

In one short statement, Portia eliminates Shylock's ability to claim his pound of flesh because it is impossible to do so without taking blood also.
To an aspiring lawyer, this clever analysis of the letter of the contract symbolizes the brilliance they hope to one day attain as lawyers. So if you're feeling blue and stressed from your legal studies, take a moment to read The Merchant of Venice and find your inspiration restored.