Within the new covenant community, the most common way the name of God is taken in vain seems to be the frivolous making of promises and failure to keep sworn oaths and vows. During the time in which the Bible was written, Israel understood that the third commandment prohibits the false swearing of oaths. Ancient commentaries on this commandment interpret it as “You shall not swear falsely by the Lord your God,” and the serious way in which the New Testament looks at oaths and vows confirms this as a proper reading (Matt. 5:33–37; James 5:12). Moreover, today’s passage tells us explicitly that to swear falsely by the name of the Lord is to treat His name as less than holy.
There are perhaps three main ways to swear an oath falsely. First, we profane God’s name if we swear by a name other than His own. We swear oaths in the presence of the Lord as a witness, in effect testifying to the parties with whom we are making a compact that if we are not true to our word, God will hold us accountable. Even when others do not pick up on our failures or when they cannot prosecute us for breaking our word, the Lord knows, and He will have the final say in the matter. To swear an oath by one other than the triune God is to usurp His judging power, His ability to prosecute an oath made by a creature of His design. Consequently, we falsely attribute power and knowledge to things and persons that really possess neither (Gal. 4:8).
Second, we abuse the name of the Lord when we swear oaths on frivolous occasions. The Westminster Confession of Faith 22.2 affirms that oaths and vows are proper only in weighty matters, largely because these are the only occasions in Scripture where we see oaths being made (Ezra 10:1–5; Ps. 132:11). Swearing oaths on frivolous occasions can be done only if we do not take God seriously.
Third, we trample upon God’s name if we make promises that we do not keep. When we do not keep a sworn oath, we act as if the Lord does not care about the truth and that He will turn a blind eye when we tell outright falsehoods or misrepresent the facts — that He will not let our lies find us out. What could be more vain or foolish than that (see Num. 32:23)?
Consider today whether you are a person of your word. Can your friends and family count on you to keep your commitments? If you consistently fail to keep your promises, then take better care to decide whether or not the promises you make can realistically be kept. It is better not to make promises than it is to promise and then fail to keep them. Let us make only promises that we are realistically able to fulfill.