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.”