As demonstrated above, there was a great deal of discussion within Second Temple Judaism on the issue of making oaths and vows. Rather than define what sorts of circumstances would allow for an oath or vow could be set aside, Jesus tells his disciples to no swear oaths of any kind. Craig Keener summarizes Jesus’s teaching here as “oaths are a poor substitute for integrity” (Matthew, 192).
Since the Law is clear God’s name cannot be used to guarantee an oath, the Jewish people would swear by other things, with varying degrees of surety. A Greek might swear by any number of gods. In the treaty of Corinth. For example, “I swear by Zeus, Gaia, Helios, Poseidon, Athena, and Ares, by all gods and goddesses, that I will maintain peace and will not break the treaties concluded with Philip of Macedon.” The Hippocratic Oath began with the words “I swear by Apollo the physician, Aesculapius, and Health, and All-heal, and all the gods and goddesses…” By invoking the name of a god the person making the oath is calling on the god to judge them if they break their word.
Jesus forbids swearing by heaven, earth or Jerusalem as well as searing by “your head.” In Matthew 23:16-22 Jesus implies the Pharisees also swore by the temple, the altar. In each case someone is substituting something for swearing by the name of God. For Jesus, any substitute for God in an oath is just as binding as swearing by God’s name.
Swearing by one’s head may refer to one’s own life. A similar phrase appears in the Mishnah:
m.San 3:2 [If] he said to him, “If one litigant said to the other, ‘I accept my father as reliable,’ ‘I accept your father as reliable,’ ‘I accept as reliable three herdsmen [to serve as judges],’ “R. Meir says, “He has the power to retract.” And sages say, “He has not got the power to retract.” [If] one owed an oath to this fellow, and his fellow said, “[Instead of an oath], take a vow to me by the life of your head,” R. Meir says, “He has the power to retract.” And sages say, “He has not got the power to retract.”
The problem with swearing by something is that breaking the vow not only dishonors the vow maker, but also the name (or thing) invoked (France, Matthew, 250). Jesus quoted the first part of Leviticus 19:12, the second have says the one who swears falsely “profanes the name of the Lord.” If one “swears to God” to do something and the oath-maker fails, the God himself is dishonored.
Rather than guaranteeing one’s word by swearing an oath, Jesus demands his disciples be truth-speaking people. The true disciple of Jesus speaks the truth and keeps their word when they give it. If someone is committed to the truth then their word will be respected and there is no need for an oath.
How can the disciple of Jesus live out this ideal of speaking the truth? Ulrich Luz points out “Once again the history of the text’s interpretation is characterized by attempting to remove the text’s sting and to soften it or to evade its demand” (Luz, Matthew 1–7, 266). The problem of “never swear an oath” is that virtually every society requires some sort of oath-making. This may be legal or economic. For example, if one gives testimony in a court case one must swear they are telling the truth. Any business relationship requiring payments is more or less an oath to pay off a debt by a certain time. Could a society function without legally binding contracts?
Most interpreters therefore argue Jesus is forbidding the sorts of frivolous oaths permitted by the traditions of the Pharisees. Pastors might extend this to flippant use of God’s name (“I swear to God…”)
It is also possible Jesus has in mind the used of God’s name in magical incantations. It was common in ancient cultures to use a god’s name in magical curses or blessings. Later magical papyri use Yahweh, Jesus, and other Christian “power words,” in modern swearing the speaker is using God’s name to invoke a curse on another: “God damn it” is calling on God to curse someone.
These are certainly appropriate applications of the respect for the name of God based on the commands of the Torah. But is this what Jesus is talking about in Matthew 5:33-37? He is demanding his disciples be known as people of integrity, people who can be trusted to keep their words so that their “yes” is just as certain as someone who has sworn an oath by the gold of the Temple.
Unfortunately, Christians do not live up to this level of integrity. Many are willing to ignore the truth if it furthers a political agenda, many are willing to state outright lies in order to score points in a public debate. Although philosophers might have debated the nature of truth for a long time, recently the American public has endured alternative facts, different interpretations of events, and errors or obvious falsifications presented as truth. Five minutes on Facebook will show that both sides of the political landscape are comfortable telling lies if it makes the other side look worse.
As Christians, we are to be people of integrity, people worthy of trust, but some of the worst lies I have read come from people who claim to follow Jesus. But it is not just politics (or what passes for political dialog today), Christians lack integrity in other areas as well. How do Christians fail to be people of integrity? Can someone regain a reputation for integrity?