Jo

The US Constitution allows federal employees (in certain circumstances) to heed Jesus' alleged proclamation that you shouldn't make per-se promises. Did Jesus actually believe this?

In Matthew, Jesus says that a religious doctrine says "'You shall not swear falsely, but carry out the vows you have made to the Lord.'" (Mt 5:33 NRSV; Ruden has "'you are not to violate your oath: you are to fulfill your oaths to the lord.'"). By the looks of it, that doctrine implies that oaths are okay, but you shouldn't break them.

Jesus, in Matthew, then goes on to say that He disagrees with that doctrine, or at least wants to add to it: "But I say to you, Do not swear at all, either by heaven, for it is by the throne of God, or by the earth, for it is his footstool, or by Jerusalem, for it is the city of the great King." By the looks of it, that statement probably implies that you should not swear by anything that is in God's direct and immediate domain, because God owns it and His ownership includes the right to swear by it. I don't think this statement alone totally rules out all swearing, because He says either by heaven or by the earth, or by Jerusalem; presumably swearing by, eg, pincushions is not prohibited by this statement alone.

Jesus, in Matthew, then goes on to say "And do not swear by your head, for you cannot make one hair white or black." In context, probably this means that you can't even swear on things that are theoretically yours more than God's ⁽¹⁾ if they will not actually enforce your commitment. (The Oxford Annotated Bible, Fifth Edition, says that the head is also under God's domain, so it's the same as swearing by the heavens; Dr Vermes suggests that you're swearing by your life, which I'll grant is definitely enforceable provided only that there's some mechanism to determine the objective veracity of your failure or success in keeping your word.)

Jesus, in Matthew, then goes on to say "Let your word be 'Yes, Yes' or 'No, No'; anything more than this comes from the evil one." (or "from evil."). This seems refreshingly straightforward…but of course it is not necessarily what it seems.

Franklin Pierce would have it that affirming something is fine (eg, "Yes, to be clear, I reiterate my statement") but placing a kind of affirmation as inherently superior to ordinary statements is a no-no; when you say "I'll do it" then you should do it 100% of the time, so there's no reason that adding the word "I swear" should change the substantive content of your statement. Cf. Philo, Decalogue 84, cited in Vermes The Authentic Gospel of Jesus 5.34; or the Essenians described by Josephus in War 2:135, cited ibid. This is what James believes; see Jm 5:12.

However, you could alternatively say that Jesus will allow you to say "I'll do it" when you're 80% sure you'll do it, and "I'll really really do it" when you're 99% sure you'll do it; He'll totally allow you to verbally communicate varying levels of commitment; the only swearing He prohibits is agreeing to a compulsion which you do not actually have the power to compel to compel you; like, if I say "And if I'm lying, may God infect the burn on my hand!" then I am attempting to subpoena God, which I do not have the power to do, whereas if I say "I really really guarantee this" then I am legitimately alleging especial certainty.

⁽²⁾

Dr Vermes suggests that the Matthew passage is against swearing by God because if you for whatever reason fail to follow through then you've just committed sacrilege; I don't think the passage can really back that interpretation, but he's probably right anyway!

(I'll put in a paragraph on what the New Interpreter's Bible says about this at some point.)

So what are we to make of this?

Let's assume that the Matthean Evangelist wrote this down word-for-word, and Jesus actually said all this in exactly this phrasing. It seems pretty clear that Jesus thinks we shouldn't guarantee our promises via enforcement mechanisms that probably won't actually function in the event of our default; in other words, don't swear by something that won't actually enforce your oath. It looks like Jesus is okay with guaranteeing something by saying "Yes definitely I super for sure guarantee it." What's really ambiguous is what Jesus thinks of backing up your guarantee with a functioning enforcement mechanism; you would assume that Jesus is okay with contracts enforceable by law, for example, and yet He does technically say that anything ⁽³⁾ more than "Yes, definitely" is the product OF SATAN!!! But in context, that kinda comes out of nowhere! Jesus explains why you should swear by (a) God, (b) the earth, (c) your head, or (e) Jerusalem, and then apparently also states flatly that you can't swear by (fghijklmnop...) anything else either, for unspecified reasons? Maybe Jesus is saying that you shouldn't use supernatural means to show the veracity of something, but using enforcement mechanisms to penalize proven breaches is okay?

What if the Matthean Evangelist got a couple details wrong? We don't know what his source was for this; it's not in Mark or Luke, probably not in Q. The author of James was at least partially working off Matthew, so who knows if he's got a good source on his interpretation. The sheer oddness of Jesus changing gears vis-a-vis certain backings for (a) oaths, versus (b) all backed oaths, might imply that the Matthean Evangelist or one of his sources did indeed screw up the reporting a bit…but let's face it, weird over-the-top condemnations out of nowhere are pretty darn in-character for Jesus.

Certainly if you believe that the entire standard-canonical New Testament is the literally true Word of God, then you definitely must believe that James is right in saying that you should never swear any oath, whether or not you're purporting any enforceability.

In conclusion, if you think that the Matthean Evangelist is reporting more or less accurately on the Word of God, then don't swear by something if you can't realistically guarantee its popping in to enforce your swearing. (That's just good sense anyway.) This category includes God, because you do not have the power to subpoena God. (Also just good sense.) You can swear oaths which are special extra-sure guarantees, at least if you're not purporting to back them up with anything besides your honesty. (This is also just practical; I want to distinguish between "Ho hum, I'm off to the post office" and "I swear to you that I will go to the post office, come heck or high water, no matter what".) If you want to play it extra safe, don't swear oaths that have any enforcement mechanisms at all (highly impractical! how am I supposed to enter into any legally enforceable contract, such as buying an orange? well, if our whole society decided to go with this interpretation, we could figure something out; look at how well Orthodox communities manage that sort of thing), though maybe you can get away with simply avoiding oaths whose intact status is determined by supernatural means (which is just good sense anyway).

I don't see any problem, Christ-wise or practical, with saying "I solemnly swear to faithfully execute the office" provided that you do in fact intend to faithfully execute the office and think it highly likely that you will; however, if you believe that James is literally true, then it would indeed be a sin.