In Jesus’ sermon on the mount we read His teaching on the subject of swearing (5:33-37). By this we do not mean profanity, which is condemned elsewhere in scripture (Colossians 3:8).
What is under consideration is the taking of an oath to establish the verity of your words. This was actually a practice that had authority under the Old Covenant. “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” (Numbers 30:2).
In Jesus’ time swearing was a common practice among both Jews and Gentiles. Vows were not made solely in God’s name, but by physical things, as alluded to by Jesus in (5:34-36): heaven, earth, Jerusalem, even by your own head.
The condemnation of swearing by your own head is especially interesting. You can’t control what happens to your head. (If I had my druthers, my hair would still be dark and full, not sparse and gray!). An oath on your head is meaningless.
As these oaths had progressed, the idea of lying for “lesser oaths” or no oath at all became more acceptable. The same is true in our days as little white lies, the breaking of our word without compunction and general dishonesty is prevalent in our society.
What Jesus requires of a child of God is complete honesty! It must be that our intent is always to do as we say we will do. “But let your ‘Yes’ be ‘Yes,’ and your ‘No,’ ‘No.’ For whatever is more than these is from the evil one” (5:37).
What we know is that Jesus condemns lying. Not only when we are under oath, or when the oath is of a lesser type. For the Christian this is an absolute. There is no place for deceit! We are told that Jesus did not lie, “guile” was not found in His mouth (1 Peter 2:22).
This has raised the question, would it be wrong for a Christian to swear to tell the truth in a court of law? It is a hard question to answer. For sure, it should not be necessary. An oath is deemed necessary when there a reason to doubt the veracity of men. With Christians, our word must always be our bond! However, those who would take this as an absolute prohibition of answering an adjuration of another would need to explain such passages as: Hebrews 6:13; Revelation 10:6; Hebrews 6:16; Matthew 26:63; 1 Thessalonians 5:27; Acts 18:18; 21:23.
What we can know is that Jesus is condemning any kind of dishonesty. He demands our ‘Yes’ be ‘Yes’ and our ‘No’ be ‘No.’ As one commentator noted, Jesus expects us to realize our own “accountability before God as the only thing needed to confirm our word” (Kyle Pope, Truth Commentary).
