Now that the fall has happened, is the moral law still useful?

WLC Q.94: Is there any use of the moral law to man since the fall?

Although no man, since the fall, can attain to righteousness and life by the moral law: (Rom. 8:3, Gal. 2:16) yet there is great use thereof, as well common to all men, as peculiar either to the unregenerate, or the regenerate. (1 Tim. 1:8)