Chapter 23. Of Lawful Oaths and Vows
Article 1. A lawful oath is a part of religious worship in which the person swearing in truth, righteousness, and judgment solemnly calls God to witness what he swears and to judge him according to the truth or falseness thereof
Article 2. Men ought to swear only by name of God, which is to be used with all holy fear and reverence Therefore, to swear vainly or rashly by that glorious and dreadful name or to swear at all by any other thing is sinful and to be abhorred. Yet, an oath is warranted by the Word of God in matters of weight and moment for confirmation of truth and ending all strife. Thus, a lawful oath being imposed by lawful authority in such matters ought to be taken.
Article 3. Whosoever takes an oath warranted by the Word of God ought duly to consider the weightiness of so solemn an act and to affirm by it nothing but what he knows to be truth, because by rash, false, and vain oaths the Lord is provoked.
Article 4. An oath is to be taken in the plain and common sense of the words without equivocation or mental reservation. It cannot oblige to sin, but when taken in anything not sinful, it binds to performance, although to a man's own hurt. It is not to be violated, although made to heretics or infidels.
Article 5. A vow is not to be made to any created being, but to God alone, and is to be made and performed with all religious care and faithfulness.
Article 6. No man may vow to do what is forbidden in the Word of God, what would hinder any duty therein commanded, or what is not in his own power and for the performance of which he has no promise of ability from God. Therefore, monastic vows of perpetual single life, professed poverty, and regular obedience are so far from being degrees of higher perfection that they are superstitious and sinful snares, in which no Christian may entangle himself.