Westminster Shorter Catechism
Q. 57. What is the fourth commandment?
The fourth commandment is: Remember the Sabbath day by keeping it holy. Six days you shall labor and do all your work but the seventh day is a Sabbath to the LORD your God. On it you shall not do any work, neither you, nor your son or daughter, nor your manservant or maidservant, nor your animals, nor the alien within your gates. For in six days the Lord made the heavens and the earth, the sea, and all that is in them, but he rested on the seventh day. Therefore the LORD blessed the Sabbath day and made it holy.
Q. 58. What does the fourth commandment require?
The fourth commandment requires us to set apart to God the times he has established in his word—specifically one whole day out of every seven as a holy Sabbath to him.
Q. 59. Which day of the week has God designated as the Sabbath?
From the beginning of the world until the resurrection of Christ, God established the seventh day of the week as the Sabbath. From that time until the end of the world, the first day of the week is the Christian Sabbath.
Q. 60. How do we keep the Sabbath holy?
We keep the Sabbath holy by resting the whole day from worldly affairs or recreations, even ones that are lawful on other days. Except for necessary works or acts of mercy, we should spend all our time publicly and privately worshipping God.
Q. 61. What does the fourth commandment forbid?
The fourth commandment forbids failing to do or carelessly doing what we are supposed to do. It also forbids treating the day as unholy by loafing, by doing anything in itself sinful, or by unnecessary thinking, talking about, or working on our worldly affairs or recreations.
Q. 62. What are the reasons for the fourth commandment?
The reasons for the fourth commandment are these: God allows us six days of the week to take care of our own affairs; he claims the seventh day as his own; he set the example, and he blesses the Sabbath.