What was the exact quote in first season of Law and Order law should be consistent but always changing?

The exact quote you are looking for is from the first episode of Law & Order, "The Pilot," and it was spoken by Adam Schiff, the District Attorney:

"The law should be consistent, but always changing."

This quote embodies the show's central theme of justice and the complexities of navigating the legal system. It highlights the need for stability within the law while acknowledging the need for it to adapt to changing societal values and circumstances.