Q: Which is the fourth commandment?
A: The fourth commandment is, Remember the sabbath-day, to keep it holy. Six days shalt thou labour, and do all thy work: but the seventh is the sabbath of the Lord thy God: in it thou shalt not do any work, thou, nor thy son, nor thy daughter, they man-servant, nor thy maid-servant, 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.

Exodus 20:8-11.

Westminster Project - John Flavel on Sabbath questions 57-59.