Question 63: Which is the fourth commandment?
Answer: The fourth commandment is, “Remember the Sabbath day to keep it holy. Six days shalt thou labor and do all thy work; but the seventh day is the Sabbath of the Lord thy God; in it thou shalt not do any work, thou, nor thy son, nor thy daughter, thy manservant, nor thy maidservant, nor thy cattle, nor thy stranger that is within thy gates: for in six days the Lord made heaven and earth, the sea, and all that in them is, and rested the seventh day: wherefore the Lord blessed the Sabbath day and hallowed it.”
Scripture: Exodus 20:8-11.
Question 64: What is required in the fourth commandment?
Answer: The fourth commandment requires the keeping holy to God such set times as he has appointed in his word, expressly one whole day in seven to be a holy Sabbath to himself.
Question 65: Which day of the seven has God appointed to be the weekly Sabbath?
Answer: From the creation of the world to the resurrection of Christ, God appointed the seventh day of the week to be the weekly Sabbath; and the first day of the week ever since, to continue to the end of the world, which is the Christian Sabbath.
The Baptist Catechism above was adapted by John Piper. This post in its entirety can be found at http://www.desiringgod.org/articles/a-baptist-catechism