Why oaths or swearing to God is of evil?

Jesus Christ in His famous sermon on the mount taught us not to swear or take oaths, even added anything more than “Yes” or “No” is of evil. In this post, we will explore why Jesus taught us not to swear and how it is of evil.

Vowing and swearing an oath in the law

Num 30:2 “If a man

  • makes a vow to the LORD, or
  • swears an oath

to bind himself by some agreement, he shall not break his word; he shall do according to all that proceeds out of his mouth.

According to the law if a man makes a vow or swears an oath to God, he must not delay to pay it because God will surely require it and it will become sin. In the above law, “some agreement” is the condition which the person vows or swears as an oath by having God as a witness.

Num 30:13 “Every vow and every binding oath to afflict her soul, ….

Vow or oaths are generally asking God to do something in exchange for “afflicting the soul”.

Jephthah’s Vow

Judg 11:30-31 And Jephthah made a vow to the LORD, and said, “

  • If You will indeed deliver the people of Ammon into my hands,
  • then it will be that whatever comes out of the doors of my house to meet me, when I return in peace from the people of Ammon, shall surely be the LORD’s, and I will offer it up as a burnt offering.” ….

In the above example, Jephthah is making a vow to the LORD. The agreement is to deliver the people of Ammon into Jephthah’s hands in exchange for a burnt offering for anything that comes out of his house.

Abraham’s Oath

Gen 21:23-24 “Now therefore, swear to me by God that you will not deal falsely with me, with my offspring, or with my posterity; but that according to the kindness that I have done to you, you will do to me and to the land in which you have dwelt.” And Abraham said, “I will swear.” …. (27-32) So Abraham took sheep and oxen and gave them to Abimelech, and the two of them made a covenant. And Abraham set seven ewe lambs of the flock by themselves. Then Abimelech asked Abraham, “What is the meaning of these seven ewe lambs which you have set by themselves?” And he said, “You will take these seven ewe lambs from my hand, that they may be my witness that I have dug this well.” Therefore he called that place Beersheba, because the two of them swore an oath there. Thus they made a covenant at Beersheba. ..

In an another example, we see how Abraham swore an oath to Abimelech, providing a “witness”and making a covenant. But you can see Abraham’s trickery. Abimalech asks Abraham to swear to him by God for one thing but Abraham swears and makes a covenant for another thing. That’s for a different discussion, but here, we can see how Abraham is swearing an oath. When swearing an oath, it requires a condition as we saw earlier and a witness must be provided. In the above example, Abraham was providing seven ewe lambs as his witness for swearing his oath that he had dug this well.

However, when Jephthah made a vow, it was a promise that he will do in return of some success from God. Comparing Jephthah’s vow with Abraham’s swearing an oath, it is affirming that his statement is true by providing a witness.

What does it mean by making a vow or swear an oath?

Heb 6:13-18 For when God made a promise to Abraham, because He could swear by no one greater, He swore by Himself, saying, “Surely blessing I will bless you, and multiplying I will multiply you.” And so, after he had patiently endured, he obtained the promise. For men indeed swear by the greater, and an oath for confirmation is for them an end of all dispute. Thus God, determining to show more abundantly to the heirs of promise the immutability of His counsel, confirmed it by an oath, that by two immutable things, in which it is impossible for God to lie, we might have strong consolation, who have fled for refuge to lay hold of the hope set before us.

As the author of Hebrews writes, people swear by someone or something greater than themselves and taking an oath to affirm their statement in order to end all disputes. In other words, if someone swears by something or someone, if he didn’t perform the oath he swore, he can be punished by the person he swore by or pay back on what he swore upon. Hence, if someone swore by God, it means, God can punish the person if what was spoken was wrong or failed to perform it. If someone swore by gold or a gift, it means, if what was spoken was wrong or failed to perform what s/he swore, s/he will pay back the gold or the gift by which he swore.

Matt 23:16-22 “Woe to you, blind guides, who say, ‘Whoever swears by the temple, it is nothing; but whoever swears by the gold of the temple, he is obliged to perform it.’ Fools and blind! For which is greater, the gold or the temple that sanctifies the gold? And, ‘Whoever swears by the altar, it is nothing; but whoever swears by the gift that is on it, he is obliged to perform it. Fools and blind! For which is greater, the gift or the altar that sanctifies the gift? Therefore,

  • he who swears by the altar, swears by it and by all things on it.
  • He who swears by the temple, swears by it and by Him who dwells in it.
  • And he who swears by heaven, swears by the throne of God and by Him who sits on it.

Jesus rebuked the scribes and Pharisees for being blind that swearing by the gold and gifts are valid and must perform it but by temple or altar is nothing. In other words, scribes and Pharisees were greedy towards gold and gifts.

Do not swear or take oaths

Matt 5:33-37 Again you have heard that it was said to those of old, ‘You shall not swear falsely, but shall perform your oaths to the Lord.’ But I say to you, do not swear at all:

  • neither by heaven, for it is God’s throne;
  • nor by the earth, for it is His footstool;
  • nor by Jerusalem, for it is the city of the great King.
  • Nor shall you swear by your head, because you cannot make one hair white or black.

But let your ‘Yes’ be ‘Yes,’ and your ‘No,’ ‘No.’ For whatever is more than these is from the evil one.

When Jesus summarising the law He states it as not to swear falsely but perform the oaths. Then, He very clearly taught us not to swear at all or take any oaths to the Lord. The reason for this is very clear, esp.,  when speaking about swearing by our head since we cannot change one hair black or white. Jesus added, anything beyond “Yes” and “No” is of evil. In other words, swearing on anything that we cannot do or have control over it, itself is swearing falsely and is from evil.


Making a vow or swearing an oath on someone greater or something which we cannot change or control is by itself swearing falsely. Hence, Jesus taught us not to swear at all. He also added anything beyond “Yes” or “No” is from evil.

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