From Our Reformed Doctrinal Standards
The Heidelberg Catechism
Questions and Answers 99-104
Q. 99. What is required in the third commandment?
A. That we, not only by cursing or perjury, but also by rash swearing, must not profane or abuse the Name of God; nor by silence or connivance be partakers of these horrible sins in others; and, briefly, that we use the holy Name of God no otherwise than with fear and reverence; so that He may be rightly confessed and worshipped by us, and be glorified in all our words and works.
Q. 100. Is then the profaning of God's Name, by swearing and cursing, so heinous a sin, that His wrath is kindled against those who do not endeavor, as much as in them lies, to prevent and forbid such cursing and swearing?
A. It undoubtedly is, for there is no sin greater or more provoking to God, than the profaning of His Name; and therefore He has commanded this sin to be punished with death.
Q. 101. May we then swear religiously by the Name of God?
A. Yes: either when the magistrates demand it of the subjects; or when necessity requires us thereby to confirm fidelity and truth to the glory of God, and the safety of our neighbor: for such an oath is founded on God's Word, and therefore was justly used by the saints, both in the Old and New Testament.
Q. 102. May we also swear by saints or any other creatures?
A. No; for a lawful oath is calling upon God, as the only One who knows the heart, that He will bear witness to the truth, and punish me if I swear falsely; which honor is due to no creature.
Q. 103. What doth God require in the fourth commandment?
A. First, that the ministry of the gospel and the schools be maintained; and that I, especially on the Sabbath, that is, on the day of rest, diligently frequent the church of God, to hear His Word, to use the sacraments, publicly to call upon the Lord, and contribute to the relief of the poor, as becomes a Christian. Secondly, that all the days of my life I cease from my evil works, and yield myself to the Lord, to work by His Holy Spirit in me: and thus begin in this life the eternal Sabbath.
Q. 104. What doth God require in the fifth commandment?
A. That I show all honor, love and fidelity, to my father and mother, and all in authority over me, and submit myself to their good instruction and correction, with due obedience; and also patiently bear with their weaknesses and infirmities, since it pleases God to govern us by their hand.