Matthew 5:33 - Meaning and Application

We have here an explanation of the third commandment, which we need to understand well, because God says he will not hold guiltless the person who takes his name in vain, even if that person thinks otherwise. This commandment clearly forbids perjury, false swearing, and breaking oaths and vows (Matthew 5:33). “You shall not use God’s name in vain,” that is, in emptiness or falsehood, is the true meaning of the commandment.

Perjury is condemned by natural conscience, because it joins evil against God with wrong against people. It also makes a person especially liable to divine anger. People have often treated false swearing as so serious that they used oaths like curses upon themselves, saying things like, “God do so to me, and more also,” or, “So help me God.” In effect, they were asking God not to help them if they were lying. By common human agreement, people have cursed themselves in this way, not doubting that God would curse them if they lied while solemnly calling him as witness.

Other Scriptures add that we must perform our oaths to the Lord (Numbers 30:2). This can mean, first, vows made directly to God, which must be paid fully and faithfully (Ecclesiastes 5:4, 5). Or it can mean promises made to other people, with God as witness to our sincerity. These must be kept with an eye to God and for his sake, because by sealing them with an oath, we have made ourselves debtors to him. If we break such a promise, we have not lied only to people, but to God.

Christ’s words also show that this commandment forbids not only false swearing, but all careless and unnecessary swearing: “Do not swear at all” (Matthew 5:34; see James 5:12). That does not mean all swearing is sinful. When it is done rightly, it is a form of worship, because it gives God the honor due to his name (Deuteronomy 6:13; Deuteronomy 10:20; Isaiah 45:23; Jeremiah 4:2). Paul himself confirmed what he said with solemn appeals when necessity required it (2 Corinthians 1:23).

When people swear, they are placing the truth of something known as a guarantee for something uncertain or unknown. They appeal to a higher witness and call on the justice of a righteous Judge if they speak falsely. Christ’s meaning here is, first, that we must not swear except when we are properly called to do so. Justice, love for our neighbor, or the good of the public may make it necessary, especially to end disputes (Hebrews 6:16). The civil ruler is usually the one who judges when that necessity exists. We may be sworn in, but we must not go looking for oaths for our own worldly gain.

Second, we must not use oaths lightly in ordinary speech. It is a very great sin to make a joke or casual reference to the glorious Majesty of heaven. Such language is holy and should always be treated with seriousness. To use God’s name that way is a gross insult to his holy name, and one of the holy things that should be set apart to the Lord. It leaves no good excuse and shows a heart without grace, where hostility toward God still rules.

Third, we must especially avoid promises made under oath, which is the main point Christ is making here, because these are oaths meant to be kept. The force of an oath about truth ends once the truth has been fully told. But a promise made under oath lasts until it is fulfilled, and it can be broken in many ways, both by surprise and by strong temptation. For that reason, it should be used only when there is great need. If oaths are often demanded, that reflects poorly on Christians, who ought to be so trustworthy that their simple word is as sacred as a solemn oath.

Fourth, we must not swear by any creature. Some people, perhaps thinking they were being respectful to God’s name, would avoid using God’s name directly and instead swear by heaven or earth. Christ forbids that here (Matthew 5:34). He shows that anything we swear by is in some way connected to God, who is the source of all things. So it is just as serious to swear by those things as by God himself, because the truth of the creature is what is being put at stake, and nothing can serve as a witness apart from its relation to God, who is the chief Truth.

So we must not swear by heaven, because it is God’s throne, where he rules and shows his glory in a special way. Since heaven belongs to him as a king’s throne belongs to the king, to swear by heaven is really to swear by God. Nor should we swear by the earth, because it is his footstool. He rules the earth as well as heaven, and though it is beneath his feet, it is still under his eye and care. The earth belongs to the Lord, so to swear by it is to swear by its Owner.

We must not swear by Jerusalem either. The Jews held that city in very high honor and thought it especially sacred to use in swearing. Yet besides its general relation to God as part of the earth, it has a special relation to him, because it is the city of the great King (Psalm 48:2), the city of God (Psalm 46:4). God is therefore concerned in every oath taken by it. Neither should we swear by our head. Though it is close to us and part of us, it belongs more to God than to us, because he made it and formed every power in it. We cannot even change one hair from white to black by our own natural power, so if we swear by our head, we are really swearing by him who gives life to the head and lifts it up (Psalm 3:3).

Therefore, in all our speech, we should be content with “Yes” and “No” (Matthew 5:37). In ordinary conversation, if we affirm something, let us say plainly, “Yes, it is so.” If needed, we may repeat it, “Yes, yes,” to show certainty. Our Lord himself used this kind of solemn truthfulness. In the same way, if we deny something, “No” should be enough, or, if needed, “No, no.” If people know we are faithful, that should be enough to win trust. If our honesty is in doubt, adding oaths and curses only makes what we say seem more suspicious. Those who can easily swallow a profane oath will not hesitate much before a lie.

It is a pity that this command, which Christ puts into the mouths of all his disciples, has been attached as a name of reproach to a group that is blameworthy enough in other ways. Dr. Hammond says we are not forbidden any more than saying yes and no, but are actually guided toward that simple way of speaking. The reason is worth noticing: whatever goes beyond these simple words comes from evil, even if it does not rise to the guilt of a formal oath.

The older text says it comes from “the evil one,” that is, from the devil. It also comes from the corruption of human nature, from strong feelings and heat of spirit, from empty pride in the mind, and from a lack of respect for holy things. It comes from the deceitfulness in people, since “all men are liars,” and so people use these extra promises because they do not trust one another and think they will not be believed without them.

Christians should therefore, for the sake of their faith’s good name, avoid not only what is plainly evil, but also what comes from evil and carries its look. Anything that comes from a bad source may itself be suspect. An oath is like medicine, and medicine assumes that there is a sickness.