The declaration states that all humans are entitled to basic rights including life, liberty, and the pursuit of happiness. It also states that if the government withholds these basic rights from citizens, citizens have the right to revolt against the government.
The declaration says that the ultimate power in a nation rests with its people.
Judges decide the law based on previous court cases according to the document called the doctrine of stare decisis. I hope that this is the answer that you were looking for and it has helped you.