167. Does He order us to labour six days a week that may rest on the seventh?
Not precisely, but in allowing us to labour for six days, He excepts the seventh, on which it is not right to be engaged.
The intention of the Fourth Commanded comes to question as to whether it is a command with the intention of making rest a privilege or a mandate. The Catechism places emphasis on the privilege of the seventh day—that it is provided as a respite from the six days of labor. However, it would seem that the command has a background in a mandate—that the believer must rest as God rested (see Question 166).
The mandate recognizes that the six days of labor and work are pushing the believer toward the rest of the Sabbath. That is, the one who would faithfully work six days should long for rest, long for the Sabbath. No member of Israel was to miss the day provided for rest and Sabbath. The exclusive nature of the command argues for its nature as mandating the day of rest.
Yet even with the mandate, that rest could never be fully achieved. The six days would make the believer long for rest, only to have the cycle repeated weekly without a longing fulfilled perpetually. It would seem that eventually the six days of work would make one long for a rest greater than a day—a rest that could be a Sabbath without end.
Work intends to point the people of God toward rest. Neither the sluggard nor workaholic understands this. The command is given to make us long for a rest on a Sabbath that only God can provide when his people have ceased from their labors as he has from his. It would therefore not be right to be engaged in work when one should be resting in the rest-Sabbath God provides. He mandates that we enjoy his rest by ceasing from our labors. The grace of the six days is that it reminds us that in both rat-race and law, our work is done, for it is Christ who provides us with rest.