What is the meaning of the saying: "The ruling revolves with its underlying cause in what is permissible and what is forbidden"?

"The ruling revolves with its cause, existing and ceasing," means that a Shariah ruling ceases when the cause for which it was legislated disappears. So, if the cause of impurity in a large volume of impure water vanishes—by the disappearance of its changed color, taste, or odor—then it becomes pure. Similarly, if the intoxicating property of wine disappears, either by transforming into vinegar or solidifying, then it becomes pure. It is a condition that the cause be an apparent and well-defined attribute.