God loves a willing people, and we should serve him with a free spirit; and vows (which are as shackles) are not to be used but in some cases of some necessity, when otherwise we cannot hold ourselves to some particulars in the worship of God, or in our daily life: and this opinion is not sound (as I think) who saith, that a work done with a vow is more laudable and acceptable, then the same work and duty done without a vow (171).
Thomas Manton — the clerk of the Westminster Assembly — wrote that the Confession together with the Larger and Shorter Catechisms presented the “substance of Christianity.” To the modern reader that may be shocking. After all, we might be convinced that the substance of Christianity can be neatly summarized in ten bullet points. A confession of faith that compromises thirty-three chapters of in-depth theology sounds, in the ears of a minimalist, like theological maximalization. Nevertheless, the Westminster Divines understood these documents as confessing and teaching the substance of Christian doctrine, worship, and piety.
Still, it may seem odd that nestled between the chapters on religious worship and the civil magistrate is a chapter on oaths and vows. It’s odd because oaths and vows don’t have a prominent place in most of our lives. Even those things that we sometimes call “vows” aren’t — strictly and confessionally speaking — vows. As Edward Morris wrote in The Theology of the Westminster Symbols: “In an inferior sense engagements, or pledges solemnly made among men, as in the marriage contract, are characterized as vows: acts of special devotion or sacrifice to some cherished interest, personal or public, are sometimes so described” (582). Neglected as oaths and vows are to many of our lives this teaching has, nevertheless, received attention within confessional Protestantism from the Augsburg Confession to the Heidelberg Catechism to the Westminster Confession.
There are, in fact, several practical reasons why this chapter has secured a place in a summary of Christian doctrine, worship, and piety. First, while oaths and vows aren’t a part of ordinary public worship they are a part of religious worship (see WCF 21.5). As a part of worship we need to understand how the Bible regulates oaths and vows. Second, as Chad VanDixhoorn noted in Confessing the Faith, those who have a high view of the State and a Christian’s civic duty will appreciate the teaching and clarity in this chapter. Even today oaths are used for elected offices, to affirm the obligations and conduct of certain professions, and for sworn testimonies. Third, this chapter represents a Protestant response to the serious errors of Roman Catholicism. J.H. Thornwell observed that Rome with its monastic system requiring vows of celibacy and poverty had erred in the truth by will-worship and superstition.