Westminster Confession Of Faith – Lord’s Day 38
Chapter 22 – Of Lawful Oaths and Vows (Cont.) (Paragraphs 4-7)
IV. An oath is to be taken in the plain and common sense of the words, without equivocation or mental reservation. It can not oblige to sin; but in any thing not sinful, being taken, it binds to performance, although to a man’s own hurt: nor is it to be violated, although made to heretics or infidels.
V. A vow is of the like nature with a promissory oath, and ought to be made with the like religious care, and to be performed with the like faithfulness.
VI. It is not to be made to any creature, but to God alone: and that it maybe accepted, it is to be made voluntarily, out of faith and conscience of duty, in way of thankfulness for mercy received, or for obtaining of what we want; whereby we more strictly bind ourselves to necessary duties, or to other things, so far and so long as they may fitly conduce thereunto.
VII. No man may vow to do any thing forbidden in the Word of God, or what would hinder any duty therein commanded, or which is not in his own power, and for the performance of which he hath no promise or ability from God. In which respects, monastical 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.