Jesus begins this section of teaching by repeating the introduction he used in verse 21. This possibly signifies a new section of teaching – a block where Jesus draws commands from other parts of the law.

There is no specific Old Testament command that Jesus refers to. He is again summarizing the teaching the people have heard. Several passages seem to apply here, such as Exodus 20:7, Leviticus 19:12, Numbers 30:2, and Deuteronomy 23:21-23.

Jesus offers a very striking contrast to what they’ve heard: “do not take an oath at all.” “The Jewish leaders had developed an incredible complexity of rules by which one could support the veracity of a statement by taking an oath …” (Osborne)

With the examples that Jesus draws upon, we get the impression that Jesus is taking issue with spurious oaths, oaths designed to allow for later release since they weren’t taken using God’s name. Jesus corrects that; all oaths are done in God’s presence. To swear by anything (heaven, earth, or Jerusalem) is to swear by God. In fact, Jesus points out that swearing by your own head is also pointless. The truthfulness of your statement can’t be guaranteed by swearing on your own head. You have no power over your own hair!

What Jesus seems to be aiming at for his people is this: total honesty, not hidden behind oaths, with responsibility for what you say. “All who submit to his authority cannot be too careful to speak only truth.” (Carson) Focusing on more and more oaths and not personal integrity comes from “evil” (or “the evil one”).

Oaths can make the truth more solemn and sure. As an example, look in Psalm 132:11: “The LORD swore to David a sure oath from which he will not turn back: ‘One of the sons of your body I will set on your throne…’” The Lord isn’t swearing an oath to force keeping his own covenant but is making the truth more solemn and sure. The truth of our words should not need oaths to confirm, yet oaths can be used to confirm the sureness of what we say (like on a witness stand or saying “I do” at the altar).

Ultimately, we live in God’s presence. He sees us and He hears us. Sinclair Ferguson said “Every promise we give, every word we speak, we do before his face.”

Deuteronomy 24:1-4 seems to be the backdrop to the teaching that Jesus picks up on next. This command from Moses dealt with limiting divorce to certain causes (“indecency”), formalizing the process to protect women who were divorced, and emphasizing the permanency of the divorce (and thus, the seriousness of marriage). (Lloyd-Jones) There were two schools of thought about that command in Jesus’ day, according to Grant Osborne. One way of thinking concluded that only sexual immorality and immodesty were reasons to divorce. Another broadened the reasons to include many causes, such as “if she spoiled a dish for him.” Jesus begins by referencing what the people had heard (vs. 5:31).

Jesus sides with a more conservative way of thinking. Sexual immorality (a very broad term in itself) is the only ground for divorce. The ESV Study Bible says that “Jesus is prohibiting divorce for the many trivial reasons that were used so frequently in the first century, leading to widespread injustice, especially for women whose husbands suddenly divorced them.”

Jesus is also saying that such sinful actions on the part of one spouse (the husband in this case) have repercussions on the other. If the woman divorced in such a way remarries, then she commits adultery – as well as her new spouse. This implies that where divorce is obtained due to sexual immorality, the second marriage of the innocent party does not begin with adultery.

So, what about re-marriage for our friends and family members who have experienced divorce not due to sexual immorality on either part (or to “desertion” by an unbelieving partner as later described by Paul)? What also does it say for family and friends who have caused a divorce? Is re-marriage an option? I believe Scripture is generally teaching here with Jesus and with Paul’s extended discussion that those so divorced should refrain from re-marrying. Each situation is unique, and my general statement can’t cover every situation. The church leadership can help believers who have been divorced understand how this biblical teaching may apply in their unique situation.