Answer

On the plain reading, this is not a commandment, and that is how it appears from most of the enumerators of the commandments. It is an introduction to the commandment to rest on the Sabbath, or at most a prohibition inferred from a positive commandment (someone who does labor on the Sabbath also violates this by neglecting a positive commandment. But someone who works does not thereby fulfill a positive commandment). However, some of the medieval authorities (Rishonim) did see this as a commandment. I seem to recall that Professor Yehuda Levi cited them in his book Sha’arei Talmud Torah.