The Weight of a Vow

The Westminster Confession of Faith, in its instructions on oath-taking, urges that great consideration be given to the “weightiness” of a vow. In the Old Testament, the Hebrew word kabod is used to speak of God’s glory. It literally means “weightiness” or “heaviness.” Of course, the word is being used metaphorically here, for God’s glory has no actual weight. But we can grasp what the Hebrews were attempting to do with this word by considering our own language. If we disregard something, we are said to take it “lightly.” However, something important or significant is said to be “heavy” or “weighty.” In like manner, the word kabod is used to communicate something about God’s overwhelming significance. Therefore, when we appeal to God to monitor and enforce our vows, it is a very weighty matter indeed. And because this is so, the confession calls us, in our oaths, “to avouch nothing but what [we are] fully persuaded is the truth.”

The confession also summarizes several additional Scriptural guidelines for oath-taking:

“No man may vow to do any thing forbidden in the Word of God, or what would hinder any duty therein commanded.” It further states that an oath “cannot oblige to sin.” We should be careful to evaluate our oaths in the light of Scripture before we swear. But if, after swearing, we find that we have vowed to do what Scripture prohibits, we may consider ourselves free of our oath, for it cannot bind us to sin.

“No man may vow to do any thing … which is not in his own power, and for the performance whereof he hath no promise of ability from God.” In other words, we must not vow to do what we know ourselves to be physically incapable of doing. Even more, we must not think that taking a vow will force God to enable us to do what we are incapable of doing. Among examples of such improper oaths the confession lists vows of chastity, poverty, and obedience.

“Nor is [an oath] to be violated, although made to heretics or infidels.” A vow must be kept, no matter how unworthy the one to whom it is made.

“A vow is of the like nature with a promissory oath, and ought … to be performed with the like faithfulness.” We must see oaths and vows as binding promises that, if legal in all respects, must be fulfilled.