What Does the Bible Teach About Oaths?

Deuteronomy 6:13 says: “Thou shalt fear the Lord thy God, and serve him, and shalt swear by his name.”

The Law of Moses never taught that oaths should be a part of one’s everyday speech. It rather taught that our word should be trustworthy all the time. Nevertheless, it also clearly taught that oaths have their place in legal matters and in other extremely serious matters.

Genesis 21:22-24: “And it came to pass at that time, that Abimelech and Phichol the chief captain of his host spoke unto Abraham, saying, God is with thee in all that thou doest: Now therefore swear unto me here by God that thou wilt not deal falsely with me, nor with my son, nor with my son’s son: but according to the kindness that I have done unto thee, thou shalt do unto me, and to the land wherein thou hast sojourned. And Abraham said, I will swear.”

It is seen in the preceding example that there is a kind of oath that is related to one’s future actions. In relation, Psalm 15:4 says that one must keep such an oath even when doing so harms them.

There is also a kind of oath which is a declaration concerning what has already happened or not happened.

Exodus 22:10-11: “If a man deliver unto his neighbor an ass (donkey), or an ox, or a sheep, or any beast, to keep; and it die, or be hurt, or driven away, no man seeing it: Then shall an oath of the Lord be between them both, that he hath not put his hand unto his neighbor’s goods; and the owner of it shall accept thereof, and he shall not make it good.”

In the very same sermon which some use to claim that Jesus forbade all oaths, Jesus actually made it clear within that sermon (the Sermon on the Mount) that He was not altering what the Law of Moses taught the slightest bit. Many also abuse the Sermon the Mount to claim He taught different than the Law of Moses in many other ways,

Matthew 5:17-18: “Think not that I am come to destroy the law, or the prophets: I am not come to destroy, but to fulfill. For verily I say unto you, Till heaven and earth pass, one jot or one tittle shall in no wise pass from the law, till all be fulfilled.”

In the Sermon on the Mount and throughout the Gospel accounts, Jesus was rather clarifying and vindicating what the Law of Moses already taught.

Matthew 7:12: “Therefore all things whatsoever ye would that men should do to you, do ye even so to them: for this is the law and the prophets.”

It is not compromising then to say that Jesus was not forbidding speaking under oath altogether when He said the following.

Matthew 5:33-37: “Again, ye have heard that it hath been said by them of old time, Thou shalt not forswear thyself, but shalt perform unto the Lord thine oaths: But I say unto you, Swear not at all; neither by heaven; for it is God’s throne: Nor by the earth; for it is his footstool: neither by Jerusalem; for it is the city of the great King. Neither shalt thou swear by thy head, because thou canst not make one hair white or black. But let your communication be, Yea, yea; Nay, nay: for whatsoever is more than these cometh of evil.”

It had become normal among the Jews for people to try to increase their credibility by making oaths frequently. It had also obviously become normal for people to swear by things such as heaven, earth, Jerusalem, or by their own heads in order to make it seem not so bad when they spoke falsely under oath. Jesus made it clear that God’s name was still blasphemed through such oaths.

In accordance with the Law of Moses, Jesus was teaching that one should be utterly truthful even if they are not under oath. Deuteronomy 6:13 had also already made it clear that, when an oath is appropriate, it should be made in God’s name. Casual oaths in everyday conversation are evil. It makes sense that “Swear not at all” is the general rule. This is said in contrast to casual swearing of oaths. Swearing under oath should be the exception that is only done when a legal matter or another especially serious matter makes this a necessity.

What Jesus said in Matthew 5:33-37 had already been taught in the Old Testament. The following verse is one example of that.

Ecclesiastes 9:2: “All things come alike to all: there is one event to the righteous, and to the wicked; to the good and to the clean (my note- “one event” here is a reference to physical death), and to the unclean; to him that sacrificeth, and to him that sacrificeth not: as is the good, so is the sinner; and he that sweareth, as he that feareth an oath.”

“He that sweareth” is the negative moral example that is put in contrast to “he that feareth an oath.” That is because it is right to treat oaths with extreme caution and to have a great fear of swearing falsely.

The following prophecy about the Messiah in the Old Testament is also particularly notable here.

Malachi 3:5: “And I will come near to you to judgment; and I will be a swift witness against the sorcerers, and against the adulterers, and against false swearers, and against those that oppress the hireling in his wages, the widow, and the fatherless, and that turn aside the stranger from his right, and fear not me, saith the Lord of hosts.”

The Messiah obviously rebuked false swearers rather than those who make truthful oaths in the name of the Lord. That is obviously how Matthew 5:33-37 should be understood.

The writer of Hebrews was not endorsing sin then when he said the following (with the implications that the oath is regarding a very serious matter and the one speaking under oath is being truthful).

Hebrews 6:16: “For men verily swear by the greater: and an oath for confirmation is to them an end of all strife.”