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Core Christianity: Tough Questions Answered

How to Swear Well {Lord’s Day 37}

by William Boekestein posted September 15, 2022

This article is part of our weekly series, “Our Life’s Comfort: One Year of Being Shaped by the Scriptures.” Read more from the series here.

(101) Q. But may we swear an oath in God’s name if we do it reverently?
A. Yes, when the government demands it, or when necessity requires it, in order to maintain and promote truth and trustworthiness for God’s glory and our neighbor’s good. Such oath-taking is grounded in God’s Word and was rightly used by the saints in the Old and New Testaments.

(102) Q. May we also swear by saints or other created things?
A. No. A legitimate oath is calling upon God as the one who knows my heart to witness to the truth and to punish me if I swear falsely. No created thing is worthy of such honor.

It is hard to imagine a time when promises meant less than they do today. Marriage partners make vows knowing that either spouse can sue for a divorce without cause; there is no longer a marital contract. We’re cynical when legal witnesses swear to tell the truth, or when elected officials vow to defend the Constitution. Have we forgotten what God’s word says about oath-taking?

This is the only commandment which the catechism spreads out over two Lord’s Days.[i] Using God’s name well is important. But because vows are religious affirmations—pledges taken in God’s name—something must also be said about swearing well.[ii] We not only must avoid blaspheming God’s name, but we must also recover the lost discipline of proper swearing.

The Validity of Oath-Taking

The writer to the Hebrews explains why people make oaths. “People swear by something greater than themselves, and in all their disputes an oath is final for confirmation” (Heb. 6:16). Humans are inherently untrusting and untrustworthy. Our commitments are often warped by ignorance and hindered by impotence. And most of the time we have to content ourselves with the unreliability of human promises; the lifetime guarantee on that product probably doesn’t mean much. But in some matters—like entering into marriage or hearing testimony in a murder trial—we must gain as much confidence as possible that we are hearing the truth. So we take oaths or swear vows. “The essence of an oath consists of calling upon God as omniscient and almighty.”[iii] When we say, “So help me God,” we’re seeking God’s assistance in telling the truth and invoking his judgment if we fail to do so.

Throughout Scripture, oaths are commanded by God and modeled by godly people. “It is the Lord your God you shall fear. Him you shall serve and by his name you shall swear” (Deut. 6:13; cf. 10:20; Exod. 22:11). Abraham (Gen. 21:24), Jacob (Gen. 31:53), David (1 Sam. 24:21–22; 2 Sam. 3:35; 1 Kings 1:29), Paul (Rom. 1:9; 9:1; 2 Cor. 1:23), and others all called on God as witness to their truth telling.

Even God takes oaths (Deut. 6:10). Jesus voluntarily accepted the terms of the oath demanded by Pilate and testified that he is “the Christ, the Son of God” (Matt. 26:63–64). God swore that he would bless Abraham, multiplying his “offspring as the stars of heaven and as the sand that is on the seashore” (Heb. 6:16–19; cf. Gen. 22:17; Ps. 95:11; 110:4). God cannot lie. But for our sake he confirmed his promise with an oath.

We may, and sometimes must, use God’s name to make an oath. But only under certain conditions.

Conditions for Oath-Taking

Oaths must be made in God’s name.

We may not “swear by saints or other created things” (like our own heart, or our mother’s grave). Jesus corrected a mistaken notion of oath-taking prevalent in his day. The Jews thought they could avoid taking God’s name in vain swearing by created things. Not so (Matt. 5:33–37). God is the greatest being who can witness to our testimony (Heb. 6:16, 13). He is the only discerner of hearts. He alone can make the future come to pass and punish those who swear falsely. For this reason, “Only a theist can swear an oath.”[iv] After all, what sense does it make for someone who doesn’t believe in God to swear to tell the truth, “God helping me”?

Oaths must only be made when necessary.

Oaths should be taken “when the government demands it, or when necessity requires it.” So for most of us oath-taking will be rare. But because oath-takers are calling on God to judge them if they are lying (1 Sam. 14:44), our oaths must “neither be rash, indiscriminate, wanton, or trifling” but must “serve a just need.”[v]

Using the Lord’s name to confirm an insignificant matter makes his name common. If you always have to say, “I promise,” or “I swear,” you probably aren’t very dependable. Though we rarely bind ourselves to oaths, people should be able to depend on what we say. When Paul was criticized for not keeping a certain plan, he defended himself like this: “When I was planning this, did I do it lightly? … [D]o I plan according to the flesh, that with me there should be Yes, Yes, and No, No?” (2 Cor. 1:17 NKJV). Christians are people of our word; we pay our debts, keep our promises, and show ourselves dependable.

Examples of Christian Oath-Taking

Especially in secular states where true vows are used less and less, few Christians will be put under oath. Still, we have important vows to make and keep.

Keep your baptismal vows.

Before the children of believers are able to make their own vows of loyalty to Christ the parents pledge in God’s name to raise their children in the faith to the utmost of their power. When the minister invokes the name of the Father, the Son, and the Holy Spirit, he impresses upon the parents the seriousness of their vow. Often entire congregations make vows to love, pray for, assist in the Christian nurture of, and encourage covenant children. These vows must be kept at all cost.

Keep your profession of faith vows.

When disciples come to the years of discretion they must, in God’s presence, fulfill the vows made for them in their baptism. “All believers have one common vow which, made in baptism, we confirm … by catechism and receiving the Lord’s Supper.” The substance of the vow is that, “renouncing Satan, we yield ourselves to God’s service to obey his holy commandments but not to follow the wicked desires of our flesh. This vow, attested by Scripture and required of all God’s children “is holy and salutary.”[vi] Professing Christians are under oath to follow Jesus.

Keep your marriage vows.

Husbands promise before God to love, honor, and maintain their wives. Wives promise before God to love, honor, and submit to their husbands in all things lawful. Marriage always gets hard. We may feel like quitting. But we didn’t merely make promises to ourselves or to another person; we promised God that we would be faithful. And there are always consequences for vow-breaking.

Keeping our word is a response to God’s grace and proof that grace makes us God-like. The God who cannot lie swears the gospel to us. “We who have fled for refuge” in Jesus “have strong encouragement to hold fast to the hope set before us” (Heb. 6:18). In light of God’s sworn mercy, how we swear matters.

[i] In the sixteenth century the radical reformers’ refusal to take oaths undermined the judicial system (see Dordrecht Confession of Faith, 1632, art. 15). For this reason the catechism authors emphasized their understanding of the biblical teaching on oaths.

[ii] John Calvin understood the third commandment to be primarily about oath-taking. Institutes, 2.8.22.

[iii] Herman Bavinck, Reformed Ethics, 206.

[iv] Herman Bavinck, Reformed Ethics, 208.

[v] Calvin, Institutes, 2.8.27

[vi] Calvin, Institutes, 4.13.6.

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