The God of the Bible is a covenant-keeping God. When He speaks, reality conforms to His word, and His promises never fail. Because we are created in His image and redeemed by His Son, our words must reflect His unwavering faithfulness. 

In a modern culture where words are cheap, contracts are routinely broken, and truth is often treated as relative, the biblical doctrine of oaths and vows might seem like an archaic relic. Yet, the Westminster Confession dedicates an entire chapter to this topic, elevating truth-telling and promise-keeping to profound theological acts.

When a witness places their hand on a Bible and says, “So help me God,” or when a couple stands at an altar and says, “Till death do us part,” they are engaging in what the Confession calls “a part of religious worship.” Chapter 22 protects the sanctity of God’s Name while guiding the Christian conscience on how to navigate the weighty promises of civil and religious life.

The Confession teaches that lawful oaths and vows are acts of worship wherein we call upon God as our witness and judge; that they must be taken with absolute integrity in the plain meaning of words; and that while they are warranted in weighty matters, we must never vow to do anything sinful, impossible, or superstitious.

The Nature and Weight of an Oath (WCF 22.1–22.3)

The Confession defines a lawful oath as an act of worship where a person “solemnly calleth God to witness what he asserteth, or promiseth, and to judge him according to the truth or falsehood of what he sweareth.”

Because an oath invokes God as the ultimate witness and judge, “The name of God only is that by which men ought to swear.” To swear flippantly (“I swear to God”), or to swear by created things (“I swear on my mother’s grave”), is a violation of the Third Commandment and is “sinful, and to be abhorred.”

During the Reformation, groups like the Anabaptists (and later the Quakers) argued that Christians should never take oaths, pointing to Jesus’s command to “swear not at all” (Matt. 5:34). However, the Westminster divines rightly understood that Jesus was condemning the Pharisees’ habit of vain, evasive, and frivolous swearing in everyday conversation. In “matters of weight and moment” (such as a court of law or taking public office), an oath is fully warranted. In fact, if a lawful civil authority requires an oath concerning something good and just, “it is a sin to refuse” it.

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