So let me get this straight — let’s suppose you have promised a stranger that you will sell them a gun. You shook on it, you gave your word. Then you find out that they have a history of domestic violence, and they have threatened to shoot someone. You could even go to prison if they act on this, using the gun you have promised to sell them, because of your lack of due diligence — “but he seemed like such a nice guy!” — but you are bound by your word — “but I promised”.
Yup. It would be morally wrong to break a promise. But of course–as in almost all cases–there are ways around this. In your example, you could go to the police and tell them you were going to sell your gun (which you have with you) to this guy who you discovered has a history of domestic violence and who has threatened to shoot someone. You could innocently ask “Do you think I should sell him this gun?” And the police–assuming an ounce of common sense–would say, “Absolutely not.” And you innocently ask, “Well, what should I do with it?” And they might say, “Turn it in to the police!” And you follow orders and now you don’t have the gun.
Or if you don’t like that example, what if you took the gun and damaged it so it wouldn’t work (I don’t know anything about guns, but I assume with some combination of a hammer, drill, and file you could do it quickly; maybe you bend the barrel a bit). Then you go to the guy and say “Hey, here’s the gun I promised, but look–it’s damaged and won’t work.”
promises always bind under pain of sin
then the only thing I could recommend, is that nobody ever promise to do anything for anyone , because you never know what kind of pickle dish you’re going to get yourself in.
Two points: As with almost every sin, there are degrees. “I promise to take the garbage out tonight” doesn’t rank up there with “I promise to marry you” or “l promise to pay back the $100,000 loan.” Just like stealing–all stealing–is wrong. Making a private photocopy at work is stealing (you are stealing the paper, toner, and use of the copier). But it hardly ranks up there with robbing a bank or embezzling $1 million.
The second point is expressed best by Ecclesiastes–
5 It is better not to promise anything than to promise something and not do it.
6 Don’t let your words cause you to sin, and don’t say to the priest at the Temple, “I didn’t mean what I promised.” If you do, God will become angry with your words and will destroy everything you have worked for.
In other words, only promise what you can deliver. Common sense. Why not say “I’ll see if I can…” or “I’ll try to…” or “I can’t think of any reason right now to stop me from…”
Now all this started because of the Republicans saying one thing in 2016 and another in 2020, esp. Lindsey Graham. So here’s one for Lindsey to think about:
Proverbs 19:1 Better is a poor man who walks in his integrity Than he who is perverse in speech and is a fool.