What did the attorney say after winning the marathon?

This joke is a prime example of wordplay, specifically a pun, that expertly blends two very different scenarios with a single phrase. The core of the humor lies in the legal term "I rest my case." In a courtroom, an attorney uses this phrase to signal to the judge and jury that they have presented all their arguments and evidence and have nothing further to add. It marks the conclusion of their formal presentation in that part of the trial.

The comedic twist comes from applying this formal legal declaration to the utterly exhausting experience of running a marathon. After completing such a strenuous physical feat, anyone's legs would be screaming for a break. By adding "and my legs" to the familiar legal saying, the joke cleverly plays on the word "rest," giving it both its legal meaning of concluding an argument and its more common meaning of taking a break from physical exertion. It's a delightful way to acknowledge both a professional victory and a very personal need for recovery.