the geneva catechism 4
161. Can the name of God we used lawfully in oaths? Yes, when they are necessary, i.e., in order to uphold the truth, when it requires it, and in maintaining love and concord among us.
162. Does He reprove no other oaths, then those which are a dishonour to God? In this one case He gives us a general instruction never to utter the name of God except with fear and humility in order to glorify it. For since it is holy and honourable, we ought to guard against taking the Name of God in such a way that we appear to hold it in contempt, or give others occasion to vilify it.
163. How is this to be done? By never thinking or speaking of God and His works without honour and reverence.
164. What follows? A warning, that He will not hold him guiltless, who takes His name in vain.
165. Since elsewhere He gives a general warning that He will punish all transgressors, what is the advantage of this warning? He wants to declare how highly He regards the glory of His name, explicitly mentioning that He will not suffer anyone to despise it, so that we may be all the more careful to hold it in reverence.
166. Let us come to the fourth commandment. Remember the Sabbath day, to keep it holy. Sis 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, thy manservant, nor thy maid-servant, nor thy cattle, nor thy stranger that is within thy gates: For in six days the Lord made haven and earth, the sea, and all that in them is, and rested the seventh day, and hallowed it.
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 in work.